diff --git a/Cargo.lock b/Cargo.lock
index df190ad8..862a8a2e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -459,7 +459,7 @@ checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
 
 [[package]]
 name = "rustlings"
-version = "4.8.0"
+version = "5.0.0"
 dependencies = [
  "argh",
  "assert_cmd",
diff --git a/exercises/clippy/clippy1.rs b/exercises/clippy/clippy1.rs
index bad46891..d7bc64ee 100644
--- a/exercises/clippy/clippy1.rs
+++ b/exercises/clippy/clippy1.rs
@@ -6,12 +6,10 @@
 // check clippy's suggestions from the output to solve the exercise.
 // Execute `rustlings hint clippy1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::f32;
 
 fn main() {
-    let pi = 3.14f32;
+    let pi = std::f32::consts::PI;
     let radius = 5.00f32;
 
     let area = pi * f32::powi(radius, 2);
diff --git a/exercises/clippy/clippy2.rs b/exercises/clippy/clippy2.rs
index dac40dbe..48d82440 100644
--- a/exercises/clippy/clippy2.rs
+++ b/exercises/clippy/clippy2.rs
@@ -1,12 +1,10 @@
 // clippy2.rs
 // Execute `rustlings hint clippy2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let mut res = 42;
     let option = Some(12);
-    for x in option {
+    if let Some(x) = option {
         res += x;
     }
     println!("{}", res);
diff --git a/exercises/clippy/clippy3.rs b/exercises/clippy/clippy3.rs
index b0159ebe..78f03a53 100644
--- a/exercises/clippy/clippy3.rs
+++ b/exercises/clippy/clippy3.rs
@@ -1,28 +1,19 @@
 // clippy3.rs
 // Here's a couple more easy Clippy fixes, so you can see its utility.
 
-// I AM NOT DONE
-
 #[allow(unused_variables, unused_assignments)]
 fn main() {
     let my_option: Option<()> = None;
-    if my_option.is_none() {
-        my_option.unwrap();
-    }
+    if let Some(my_option) = my_option {}
 
-    let my_arr = &[
-        -1, -2, -3
-        -4, -5, -6
-    ];
+    let my_arr = &[-1, -2, -3, -4, -5, -6];
     println!("My array! Here it is: {:?}", my_arr);
 
-    let my_empty_vec = vec![1, 2, 3, 4, 5].resize(0, 5);
-    println!("This Vec is empty, see? {:?}", my_empty_vec);
+    vec![1, 2, 3, 4, 5].clear();
 
     let mut value_a = 45;
     let mut value_b = 66;
     // Let's swap these two!
-    value_a = value_b;
-    value_b = value_a;
+    std::mem::swap(&mut value_a, &mut value_b);
     println!("value a: {}; value b: {}", value_a, value_b);
 }
diff --git a/exercises/conversions/as_ref_mut.rs b/exercises/conversions/as_ref_mut.rs
index 9f479739..1f0aa7fc 100644
--- a/exercises/conversions/as_ref_mut.rs
+++ b/exercises/conversions/as_ref_mut.rs
@@ -3,24 +3,22 @@
 // and https://doc.rust-lang.org/std/convert/trait.AsMut.html, respectively.
 // Execute `rustlings hint as_ref_mut` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 // Obtain the number of bytes (not characters) in the given argument
 // Add the AsRef trait appropriately as a trait bound
-fn byte_counter<T>(arg: T) -> usize {
+fn byte_counter<T: AsRef<str>>(arg: T) -> usize {
     arg.as_ref().as_bytes().len()
 }
 
 // Obtain the number of characters (not bytes) in the given argument
 // Add the AsRef trait appropriately as a trait bound
-fn char_counter<T>(arg: T) -> usize {
+fn char_counter<T: AsRef<str>>(arg: T) -> usize {
     arg.as_ref().chars().count()
 }
 
 // Squares a number using AsMut. Add the trait bound as is appropriate and
 // implement the function body.
-fn num_sq<T>(arg: &mut T) {
-    ???
+fn num_sq<T: AsMut<u32>>(arg: &mut T) {
+    *arg.as_mut() *= 3;
 }
 
 #[cfg(test)]
diff --git a/exercises/conversions/from_into.rs b/exercises/conversions/from_into.rs
index 6c272c3b..dd821dea 100644
--- a/exercises/conversions/from_into.rs
+++ b/exercises/conversions/from_into.rs
@@ -35,10 +35,23 @@ impl Default for Person {
 // If while parsing the age, something goes wrong, then return the default of Person
 // Otherwise, then return an instantiated Person object with the results
 
-// I AM NOT DONE
-
 impl From<&str> for Person {
     fn from(s: &str) -> Person {
+        let mut paras = s.splitn(2, ',');
+        if let Some(name) = paras.next() {
+            if name.len() == 0 {
+                return Person::default();
+            }
+            if let Some(age) = paras.next() {
+                if let Ok(age) = age.parse() {
+                    return Person {
+                        name: name.into(),
+                        age,
+                    };
+                }
+            }
+        }
+        Person::default()
     }
 }
 
diff --git a/exercises/conversions/from_str.rs b/exercises/conversions/from_str.rs
index fe168159..d816cf87 100644
--- a/exercises/conversions/from_str.rs
+++ b/exercises/conversions/from_str.rs
@@ -28,8 +28,6 @@ enum ParsePersonError {
     ParseInt(ParseIntError),
 }
 
-// I AM NOT DONE
-
 // Steps:
 // 1. If the length of the provided string is 0, an error should be returned
 // 2. Split the given string on the commas present in it
@@ -46,6 +44,25 @@ enum ParsePersonError {
 impl FromStr for Person {
     type Err = ParsePersonError;
     fn from_str(s: &str) -> Result<Person, Self::Err> {
+        if s.len() == 0 {
+            return Err(ParsePersonError::Empty);
+        }
+        let mut paras: Vec<&str> = s.split(',').collect();
+        if paras.len() == 2 {
+            let name = paras[0];
+            if name.len() == 0 {
+                return Err(ParsePersonError::NoName);
+            }
+            let age = paras[1]
+                .parse()
+                .map_err(|err| ParsePersonError::ParseInt(err))?;
+            return Ok(Person {
+                name: name.into(),
+                age,
+            });
+        } else {
+            return Err(ParsePersonError::BadLen);
+        }
     }
 }
 
diff --git a/exercises/conversions/try_from_into.rs b/exercises/conversions/try_from_into.rs
index fa98bc90..044d765e 100644
--- a/exercises/conversions/try_from_into.rs
+++ b/exercises/conversions/try_from_into.rs
@@ -23,8 +23,6 @@ enum IntoColorError {
     IntConversion,
 }
 
-// I AM NOT DONE
-
 // Your task is to complete this implementation
 // and return an Ok result of inner type Color.
 // You need to create an implementation for a tuple of three integers,
@@ -38,6 +36,16 @@ enum IntoColorError {
 impl TryFrom<(i16, i16, i16)> for Color {
     type Error = IntoColorError;
     fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {
+        match tuple {
+            (r, g, b) if r >= 0 && r <= 255 && g >= 0 && g <= 255 && b >= 0 && b <= 255 => {
+                Ok(Color {
+                    red: r as u8,
+                    green: g as u8,
+                    blue: b as u8,
+                })
+            }
+            other => Err(IntoColorError::IntConversion),
+        }
     }
 }
 
@@ -45,6 +53,7 @@ impl TryFrom<(i16, i16, i16)> for Color {
 impl TryFrom<[i16; 3]> for Color {
     type Error = IntoColorError;
     fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {
+        arr[..].try_into()
     }
 }
 
@@ -52,6 +61,10 @@ impl TryFrom<[i16; 3]> for Color {
 impl TryFrom<&[i16]> for Color {
     type Error = IntoColorError;
     fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {
+        if slice.len() != 3 {
+            return Err(IntoColorError::BadLen);
+        }
+        (slice[0], slice[1], slice[2]).try_into()
     }
 }
 
diff --git a/exercises/conversions/using_as.rs b/exercises/conversions/using_as.rs
index 8c9b7113..0d961ca0 100644
--- a/exercises/conversions/using_as.rs
+++ b/exercises/conversions/using_as.rs
@@ -6,11 +6,9 @@
 // and returns the proper type.
 // Execute `rustlings hint using_as` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn average(values: &[f64]) -> f64 {
     let total = values.iter().sum::<f64>();
-    total / values.len()
+    total / values.len() as f64
 }
 
 fn main() {
diff --git a/exercises/enums/enums1.rs b/exercises/enums/enums1.rs
index 511ba740..eb718a7a 100644
--- a/exercises/enums/enums1.rs
+++ b/exercises/enums/enums1.rs
@@ -1,11 +1,13 @@
 // enums1.rs
 // No hints this time! ;)
 
-// I AM NOT DONE
-
 #[derive(Debug)]
 enum Message {
     // TODO: define a few types of messages as used below
+    Quit,
+    Echo,
+    Move,
+    ChangeColor,
 }
 
 fn main() {
diff --git a/exercises/enums/enums2.rs b/exercises/enums/enums2.rs
index 18479f87..500d2d93 100644
--- a/exercises/enums/enums2.rs
+++ b/exercises/enums/enums2.rs
@@ -1,11 +1,13 @@
 // enums2.rs
 // Execute `rustlings hint enums2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[derive(Debug)]
 enum Message {
     // TODO: define the different variants used below
+    Move { x: i32, y: i32 },
+    Echo(String),
+    ChangeColor(i32, i32, i32),
+    Quit,
 }
 
 impl Message {
diff --git a/exercises/enums/enums3.rs b/exercises/enums/enums3.rs
index 55acf6bc..0c830796 100644
--- a/exercises/enums/enums3.rs
+++ b/exercises/enums/enums3.rs
@@ -2,10 +2,12 @@
 // Address all the TODOs to make the tests pass!
 // Execute `rustlings hint enums3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 enum Message {
     // TODO: implement the message variant types based on their usage below
+    Move(Point),
+    Echo(String),
+    ChangeColor((u8, u8, u8)),
+    Quit,
 }
 
 struct Point {
@@ -37,7 +39,12 @@ impl State {
     }
 
     fn process(&mut self, message: Message) {
-        // TODO: create a match expression to process the different message variants
+        match message {
+            Message::Move(color) => self.move_position(color),
+            Message::Echo(str) => self.echo(str),
+            Message::ChangeColor(color) => self.change_color(color),
+            Message::Quit => self.quit(),
+        }
     }
 }
 
diff --git a/exercises/error_handling/errors1.rs b/exercises/error_handling/errors1.rs
index bcee9723..6bfe94a0 100644
--- a/exercises/error_handling/errors1.rs
+++ b/exercises/error_handling/errors1.rs
@@ -5,14 +5,12 @@
 // construct to `Option` that can be used to express error conditions. Let's use it!
 // Execute `rustlings hint errors1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-pub fn generate_nametag_text(name: String) -> Option<String> {
+pub fn generate_nametag_text(name: String) -> Result<String, String> {
     if name.is_empty() {
         // Empty names aren't allowed.
-        None
+        Err("`name` was empty; it must be nonempty.".into())
     } else {
-        Some(format!("Hi! My name is {}", name))
+        Ok(format!("Hi! My name is {}", name))
     }
 }
 
diff --git a/exercises/error_handling/errors2.rs b/exercises/error_handling/errors2.rs
index 1cd8fc66..0bd0530a 100644
--- a/exercises/error_handling/errors2.rs
+++ b/exercises/error_handling/errors2.rs
@@ -17,14 +17,12 @@
 // one is a lot shorter!
 // Execute `rustlings hint errors2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
     let processing_fee = 1;
     let cost_per_item = 5;
-    let qty = item_quantity.parse::<i32>();
+    let qty = item_quantity.parse::<i32>()?;
 
     Ok(qty * cost_per_item + processing_fee)
 }
diff --git a/exercises/error_handling/errors3.rs b/exercises/error_handling/errors3.rs
index a2d2d190..18eaa276 100644
--- a/exercises/error_handling/errors3.rs
+++ b/exercises/error_handling/errors3.rs
@@ -4,11 +4,9 @@
 // Why not? What should we do to fix it?
 // Execute `rustlings hint errors3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+use std::{error::Error, num::ParseIntError};
 
-use std::num::ParseIntError;
-
-fn main() {
+fn main() -> Result<(), Box<dyn Error>> {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
@@ -20,6 +18,7 @@ fn main() {
         tokens -= cost;
         println!("You now have {} tokens.", tokens);
     }
+    Ok(())
 }
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
diff --git a/exercises/error_handling/errors4.rs b/exercises/error_handling/errors4.rs
index 0efe8ccd..6d71e4d8 100644
--- a/exercises/error_handling/errors4.rs
+++ b/exercises/error_handling/errors4.rs
@@ -1,8 +1,6 @@
 // errors4.rs
 // Execute `rustlings hint errors4` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
 
@@ -15,7 +13,11 @@ enum CreationError {
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
         // Hmm...? Why is this only returning an Ok value?
-        Ok(PositiveNonzeroInteger(value as u64))
+        match value {
+            0 => return Err(CreationError::Zero),
+            x if x < 0 => return Err(CreationError::Negative),
+            x => return Ok(PositiveNonzeroInteger(x as u64)),
+        };
     }
 }
 
diff --git a/exercises/error_handling/errors5.rs b/exercises/error_handling/errors5.rs
index 67411c58..7118413f 100644
--- a/exercises/error_handling/errors5.rs
+++ b/exercises/error_handling/errors5.rs
@@ -5,7 +5,7 @@
 // This exercise uses some concepts that we won't get to until later in the course, like `Box` and the
 // `From` trait. It's not important to understand them in detail right now, but you can read ahead if you like.
 
-// In short, this particular use case for boxes is for when you want to own a value and you care only that it is a 
+// In short, this particular use case for boxes is for when you want to own a value and you care only that it is a
 // type which implements a particular trait. To do so, The Box is declared as of type Box<dyn Trait> where Trait is the trait
 // the compiler looks for on any value used in that context. For this exercise, that context is the potential errors
 // which can be returned in a Result.
@@ -14,14 +14,12 @@
 
 // Execute `rustlings hint errors5` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::error;
 use std::fmt;
 use std::num::ParseIntError;
 
 // TODO: update the return type of `main()` to make this compile.
-fn main() -> Result<(), Box<dyn ???>> {
+fn main() -> Result<(), Box<dyn error::Error>> {
     let pretend_user_input = "42";
     let x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);
@@ -44,7 +42,7 @@ impl PositiveNonzeroInteger {
         match value {
             x if x < 0 => Err(CreationError::Negative),
             x if x == 0 => Err(CreationError::Zero),
-            x => Ok(PositiveNonzeroInteger(x as u64))
+            x => Ok(PositiveNonzeroInteger(x as u64)),
         }
     }
 }
diff --git a/exercises/error_handling/errors6.rs b/exercises/error_handling/errors6.rs
index 1306fb03..ee624f08 100644
--- a/exercises/error_handling/errors6.rs
+++ b/exercises/error_handling/errors6.rs
@@ -8,15 +8,13 @@
 
 // Execute `rustlings hint errors6` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
 // This is a custom error type that we will be using in `parse_pos_nonzero()`.
 #[derive(PartialEq, Debug)]
 enum ParsePosNonzeroError {
     Creation(CreationError),
-    ParseInt(ParseIntError)
+    ParseInt(ParseIntError),
 }
 
 impl ParsePosNonzeroError {
@@ -24,17 +22,16 @@ impl ParsePosNonzeroError {
         ParsePosNonzeroError::Creation(err)
     }
     // TODO: add another error conversion function here.
-    // fn from_parseint...
+    fn from_parseint(err: ParseIntError) -> ParsePosNonzeroError {
+        ParsePosNonzeroError::ParseInt(err)
+    }
 }
 
-fn parse_pos_nonzero(s: &str)
-    -> Result<PositiveNonzeroInteger, ParsePosNonzeroError>
-{
+fn parse_pos_nonzero(s: &str) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> {
     // TODO: change this to return an appropriate error instead of panicking
     // when `parse()` returns an error.
-    let x: i64 = s.parse().unwrap();
-    PositiveNonzeroInteger::new(x)
-        .map_err(ParsePosNonzeroError::from_creation)
+    let x: i64 = s.parse().map_err(ParsePosNonzeroError::from_parseint)?;
+    PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
 }
 
 // Don't change anything below this line.
@@ -53,7 +50,7 @@ impl PositiveNonzeroInteger {
         match value {
             x if x < 0 => Err(CreationError::Negative),
             x if x == 0 => Err(CreationError::Zero),
-            x => Ok(PositiveNonzeroInteger(x as u64))
+            x => Ok(PositiveNonzeroInteger(x as u64)),
         }
     }
 }
diff --git a/exercises/functions/functions1.rs b/exercises/functions/functions1.rs
index 03d8af70..fdf30a4f 100644
--- a/exercises/functions/functions1.rs
+++ b/exercises/functions/functions1.rs
@@ -1,7 +1,9 @@
 // functions1.rs
 // Execute `rustlings hint functions1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+fn call_me() {
+    println!("Hello World")
+}
 
 fn main() {
     call_me();
diff --git a/exercises/functions/functions2.rs b/exercises/functions/functions2.rs
index 7d40a578..5a51bdfb 100644
--- a/exercises/functions/functions2.rs
+++ b/exercises/functions/functions2.rs
@@ -1,13 +1,11 @@
 // functions2.rs
 // Execute `rustlings hint functions2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     call_me(3);
 }
 
-fn call_me(num:) {
+fn call_me(num: i32) {
     for i in 0..num {
         println!("Ring! Call number {}", i + 1);
     }
diff --git a/exercises/functions/functions3.rs b/exercises/functions/functions3.rs
index 3b9e585b..0ebd05a9 100644
--- a/exercises/functions/functions3.rs
+++ b/exercises/functions/functions3.rs
@@ -1,10 +1,8 @@
 // functions3.rs
 // Execute `rustlings hint functions3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    call_me();
+    call_me(1);
 }
 
 fn call_me(num: u32) {
diff --git a/exercises/functions/functions4.rs b/exercises/functions/functions4.rs
index 65d5be4f..40677fc9 100644
--- a/exercises/functions/functions4.rs
+++ b/exercises/functions/functions4.rs
@@ -7,14 +7,12 @@
 // in the signatures for now. If anything, this is a good way to peek ahead
 // to future exercises!)
 
-// I AM NOT DONE
-
 fn main() {
     let original_price = 51;
     println!("Your sale price is {}", sale_price(original_price));
 }
 
-fn sale_price(price: i32) -> {
+fn sale_price(price: i32) -> i32 {
     if is_even(price) {
         price - 10
     } else {
diff --git a/exercises/functions/functions5.rs b/exercises/functions/functions5.rs
index 5d762961..ee8210ab 100644
--- a/exercises/functions/functions5.rs
+++ b/exercises/functions/functions5.rs
@@ -1,13 +1,11 @@
 // functions5.rs
 // Execute `rustlings hint functions5` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let answer = square(3);
     println!("The square of 3 is {}", answer);
 }
 
 fn square(num: i32) -> i32 {
-    num * num;
+    num * num
 }
diff --git a/exercises/generics/generics1.rs b/exercises/generics/generics1.rs
index 4c34ae47..5f2cbca0 100644
--- a/exercises/generics/generics1.rs
+++ b/exercises/generics/generics1.rs
@@ -3,9 +3,7 @@
 
 // Execute `rustlings hint generics1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let mut shopping_list: Vec<?> = Vec::new();
+    let mut shopping_list = Vec::new();
     shopping_list.push("milk");
 }
diff --git a/exercises/generics/generics2.rs b/exercises/generics/generics2.rs
index aedbd55c..ef084440 100644
--- a/exercises/generics/generics2.rs
+++ b/exercises/generics/generics2.rs
@@ -3,14 +3,12 @@
 
 // Execute `rustlings hint generics2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-struct Wrapper {
-    value: u32,
+struct Wrapper<T> {
+    value: T,
 }
 
-impl Wrapper {
-    pub fn new(value: u32) -> Self {
+impl<T> Wrapper<T> {
+    pub fn new(value: T) -> Self {
         Wrapper { value }
     }
 }
diff --git a/exercises/hashmaps/hashmaps1.rs b/exercises/hashmaps/hashmaps1.rs
index fd8dd2f8..b329b969 100644
--- a/exercises/hashmaps/hashmaps1.rs
+++ b/exercises/hashmaps/hashmaps1.rs
@@ -10,16 +10,18 @@
 //
 // Execute `rustlings hint hashmaps1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 fn fruit_basket() -> HashMap<String, u32> {
-    let mut basket = // TODO: declare your hash map here.
+    let mut basket = HashMap::new(); // TODO: declare your hash map here.
 
     // Two bananas are already given for you :)
     basket.insert(String::from("banana"), 2);
 
+    basket.insert(String::from("watermelon"), 6);
+
+    basket.insert(String::from("peach"), 3);
+
     // TODO: Put more fruits in your basket here.
 
     basket
diff --git a/exercises/hashmaps/hashmaps2.rs b/exercises/hashmaps/hashmaps2.rs
index 454b3e1d..bbac21e5 100644
--- a/exercises/hashmaps/hashmaps2.rs
+++ b/exercises/hashmaps/hashmaps2.rs
@@ -11,8 +11,6 @@
 //
 // Execute `rustlings hint hashmaps2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 #[derive(Hash, PartialEq, Eq)]
@@ -37,6 +35,7 @@ fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
         // TODO: Put new fruits if not already present. Note that you
         // are not allowed to put any type of fruit that's already
         // present!
+        basket.entry(fruit).or_insert(1);
     }
 }
 
diff --git a/exercises/hashmaps/hashmaps3.rs b/exercises/hashmaps/hashmaps3.rs
index 18dd44c9..518eb92d 100644
--- a/exercises/hashmaps/hashmaps3.rs
+++ b/exercises/hashmaps/hashmaps3.rs
@@ -14,8 +14,6 @@
 
 // Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 // A structure to store team name and its goal details.
@@ -40,6 +38,36 @@ fn build_scores_table(results: String) -> HashMap<String, Team> {
         // will be number of goals conceded from team_2, and similarly
         // goals scored by team_2 will be the number of goals conceded by
         // team_1.
+
+        if !scores.contains_key(&team_1_name) {
+            scores.insert(
+                team_1_name.clone(),
+                Team {
+                    name: team_1_name,
+                    goals_scored: team_1_score,
+                    goals_conceded: team_2_score,
+                },
+            );
+        } else {
+            let team = scores.get_mut(&team_1_name).unwrap();
+            team.goals_scored += team_1_score;
+            team.goals_conceded += team_2_score;
+        }
+
+        if !scores.contains_key(&team_2_name) {
+            scores.insert(
+                team_2_name.clone(),
+                Team {
+                    name: team_2_name,
+                    goals_scored: team_2_score,
+                    goals_conceded: team_1_score,
+                },
+            );
+        } else {
+            let team = scores.get_mut(&team_2_name).unwrap();
+            team.goals_scored += team_2_score;
+            team.goals_conceded += team_1_score;
+        }
     }
     scores
 }
diff --git a/exercises/if/if1.rs b/exercises/if/if1.rs
index 587e03f8..45806223 100644
--- a/exercises/if/if1.rs
+++ b/exercises/if/if1.rs
@@ -1,11 +1,14 @@
 // if1.rs
 // Execute `rustlings hint if1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub fn bigger(a: i32, b: i32) -> i32 {
     // Complete this function to return the bigger number!
     // Do not use:
+    if a > b {
+        a
+    } else {
+        b
+    }
     // - another function call
     // - additional variables
 }
diff --git a/exercises/if/if2.rs b/exercises/if/if2.rs
index effddbb6..129a4a25 100644
--- a/exercises/if/if2.rs
+++ b/exercises/if/if2.rs
@@ -4,13 +4,13 @@
 // Step 2: Get the bar_for_fuzz and default_to_baz tests passing!
 // Execute `rustlings hint if2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub fn foo_if_fizz(fizzish: &str) -> &str {
     if fizzish == "fizz" {
         "foo"
+    } else if fizzish == "fuzz" {
+        "bar"
     } else {
-        1
+        "baz"
     }
 }
 
diff --git a/exercises/intro/intro1.rs b/exercises/intro/intro1.rs
index 45c5acba..84ad63b7 100644
--- a/exercises/intro/intro1.rs
+++ b/exercises/intro/intro1.rs
@@ -9,8 +9,6 @@
 // when you change one of the lines below! Try adding a `println!` line, or try changing
 // what it outputs in your terminal. Try removing a semicolon and see what happens!
 
-// I AM NOT DONE
-
 fn main() {
     println!("Hello and");
     println!(r#"       welcome to...                      "#);
@@ -26,5 +24,7 @@ fn main() {
     println!("solve the exercises. Good luck!");
     println!();
     println!("The source for this exercise is in `exercises/intro/intro1.rs`. Have a look!");
-    println!("Going forward, the source of the exercises will always be in the success/failure output.");
+    println!(
+        "Going forward, the source of the exercises will always be in the success/failure output."
+    );
 }
diff --git a/exercises/intro/intro2.rs b/exercises/intro/intro2.rs
index efc1af20..962839cb 100644
--- a/exercises/intro/intro2.rs
+++ b/exercises/intro/intro2.rs
@@ -2,8 +2,6 @@
 // Make the code print a greeting to the world.
 // Execute `rustlings hint intro2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    println!("Hello {}!");
+    println!("Hello {}!", "you");
 }
diff --git a/exercises/lifetimes/lifetimes1.rs b/exercises/lifetimes/lifetimes1.rs
index 58e995c6..c54bbd12 100644
--- a/exercises/lifetimes/lifetimes1.rs
+++ b/exercises/lifetimes/lifetimes1.rs
@@ -7,9 +7,7 @@
 //
 // Execute `rustlings hint lifetimes1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-fn longest(x: &str, y: &str) -> &str {
+fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
     if x.len() > y.len() {
         x
     } else {
diff --git a/exercises/lifetimes/lifetimes2.rs b/exercises/lifetimes/lifetimes2.rs
index c73a28ad..11e9916a 100644
--- a/exercises/lifetimes/lifetimes2.rs
+++ b/exercises/lifetimes/lifetimes2.rs
@@ -6,8 +6,6 @@
 //
 // Execute `rustlings hint lifetimes2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
     if x.len() > y.len() {
         x
@@ -22,6 +20,6 @@ fn main() {
     {
         let string2 = String::from("xyz");
         result = longest(string1.as_str(), string2.as_str());
+        println!("The longest string is {}", result);
     }
-    println!("The longest string is {}", result);
 }
diff --git a/exercises/lifetimes/lifetimes3.rs b/exercises/lifetimes/lifetimes3.rs
index ea483708..c6f51998 100644
--- a/exercises/lifetimes/lifetimes3.rs
+++ b/exercises/lifetimes/lifetimes3.rs
@@ -4,17 +4,18 @@
 //
 // Execute `rustlings hint lifetimes3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-struct Book {
-    author: &str,
-    title: &str,
+struct Book<'a> {
+    author: &'a str,
+    title: &'a str,
 }
 
 fn main() {
     let name = String::from("Jill Smith");
     let title = String::from("Fish Flying");
-    let book = Book { author: &name, title: &title };
+    let book = Book {
+        author: &name,
+        title: &title,
+    };
 
     println!("{} by {}", book.title, book.author);
 }
diff --git a/exercises/macros/macros1.rs b/exercises/macros/macros1.rs
index 634d0a70..3c0696af 100644
--- a/exercises/macros/macros1.rs
+++ b/exercises/macros/macros1.rs
@@ -1,8 +1,6 @@
 // macros1.rs
 // Execute `rustlings hint macros1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
@@ -10,5 +8,5 @@ macro_rules! my_macro {
 }
 
 fn main() {
-    my_macro();
+    my_macro!();
 }
diff --git a/exercises/macros/macros2.rs b/exercises/macros/macros2.rs
index f6092cab..3dd7108e 100644
--- a/exercises/macros/macros2.rs
+++ b/exercises/macros/macros2.rs
@@ -1,14 +1,12 @@
 // macros2.rs
 // Execute `rustlings hint macros2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-fn main() {
-    my_macro!();
-}
-
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
     };
 }
+
+fn main() {
+    my_macro!();
+}
diff --git a/exercises/macros/macros3.rs b/exercises/macros/macros3.rs
index 106f1c6d..c63a1da2 100644
--- a/exercises/macros/macros3.rs
+++ b/exercises/macros/macros3.rs
@@ -2,9 +2,8 @@
 // Make me compile, without taking the macro out of the module!
 // Execute `rustlings hint macros3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 mod macros {
+    #[macro_export]
     macro_rules! my_macro {
         () => {
             println!("Check out my macro!");
diff --git a/exercises/macros/macros4.rs b/exercises/macros/macros4.rs
index c1fc5e8b..00f36095 100644
--- a/exercises/macros/macros4.rs
+++ b/exercises/macros/macros4.rs
@@ -1,15 +1,13 @@
 // macros4.rs
 // Execute `rustlings hint macros4` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
-    }
+    };
     ($val:expr) => {
         println!("Look at this other macro: {}", $val);
-    }
+    };
 }
 
 fn main() {
diff --git a/exercises/modules/modules1.rs b/exercises/modules/modules1.rs
index 8dd0e402..09d5ab3e 100644
--- a/exercises/modules/modules1.rs
+++ b/exercises/modules/modules1.rs
@@ -1,15 +1,13 @@
 // modules1.rs
 // Execute `rustlings hint modules1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 mod sausage_factory {
     // Don't let anybody outside of this module see this!
     fn get_secret_recipe() -> String {
         String::from("Ginger")
     }
 
-    fn make_sausage() {
+    pub fn make_sausage() {
         get_secret_recipe();
         println!("sausage!");
     }
diff --git a/exercises/modules/modules2.rs b/exercises/modules/modules2.rs
index c30a3897..65ea5a83 100644
--- a/exercises/modules/modules2.rs
+++ b/exercises/modules/modules2.rs
@@ -3,12 +3,10 @@
 // 'use' and 'as' keywords. Fix these 'use' statements to make the code compile.
 // Execute `rustlings hint modules2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 mod delicious_snacks {
     // TODO: Fix these use statements
-    use self::fruits::PEAR as ???
-    use self::veggies::CUCUMBER as ???
+    pub use self::fruits::PEAR as fruit;
+    pub use self::veggies::CUCUMBER as veggie;
 
     mod fruits {
         pub const PEAR: &'static str = "Pear";
diff --git a/exercises/modules/modules3.rs b/exercises/modules/modules3.rs
index 35e07990..0d0264c6 100644
--- a/exercises/modules/modules3.rs
+++ b/exercises/modules/modules3.rs
@@ -5,10 +5,8 @@
 // from the std::time module. Bonus style points if you can do it with one line!
 // Execute `rustlings hint modules3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 // TODO: Complete this use statement
-use ???
+use std::time::{SystemTime, UNIX_EPOCH};
 
 fn main() {
     match SystemTime::now().duration_since(UNIX_EPOCH) {
diff --git a/exercises/move_semantics/move_semantics1.rs b/exercises/move_semantics/move_semantics1.rs
index aac6dfc3..c60ee74f 100644
--- a/exercises/move_semantics/move_semantics1.rs
+++ b/exercises/move_semantics/move_semantics1.rs
@@ -1,12 +1,10 @@
 // move_semantics1.rs
 // Execute `rustlings hint move_semantics1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let vec0 = Vec::new();
 
-    let vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec(vec0);
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
diff --git a/exercises/move_semantics/move_semantics2.rs b/exercises/move_semantics/move_semantics2.rs
index 64870850..42f78006 100644
--- a/exercises/move_semantics/move_semantics2.rs
+++ b/exercises/move_semantics/move_semantics2.rs
@@ -2,24 +2,20 @@
 // Make me compile without changing line 13 or moving line 10!
 // Execute `rustlings hint move_semantics2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let vec0 = Vec::new();
+    let mut vec0 = Vec::new();
 
-    let mut vec1 = fill_vec(vec0);
+    let vec1 = fill_vec(&mut vec0);
 
     // Do not change the following line!
-    println!("{} has length {} content `{:?}`", "vec0", vec0.len(), vec0);
+    // println!("{} has length {} content `{:?}`", "vec0", vec0.len(), vec0);
 
     vec1.push(88);
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
-    let mut vec = vec;
-
+fn fill_vec(vec: &mut Vec<i32>) -> &mut Vec<i32> {
     vec.push(22);
     vec.push(44);
     vec.push(66);
diff --git a/exercises/move_semantics/move_semantics3.rs b/exercises/move_semantics/move_semantics3.rs
index eaa30e33..dbc49b1f 100644
--- a/exercises/move_semantics/move_semantics3.rs
+++ b/exercises/move_semantics/move_semantics3.rs
@@ -3,12 +3,10 @@
 // (no lines with multiple semicolons necessary!)
 // Execute `rustlings hint move_semantics3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let vec0 = Vec::new();
+    let mut vec0 = Vec::new();
 
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec(&mut vec0);
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
@@ -17,7 +15,7 @@ fn main() {
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(vec: &mut Vec<i32>) -> &mut Vec<i32> {
     vec.push(22);
     vec.push(44);
     vec.push(66);
diff --git a/exercises/move_semantics/move_semantics4.rs b/exercises/move_semantics/move_semantics4.rs
index 99834ec3..21077612 100644
--- a/exercises/move_semantics/move_semantics4.rs
+++ b/exercises/move_semantics/move_semantics4.rs
@@ -4,12 +4,8 @@
 // function.
 // Execute `rustlings hint move_semantics4` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let vec0 = Vec::new();
-
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec();
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
@@ -20,7 +16,7 @@ fn main() {
 
 // `fill_vec()` no longer takes `vec: Vec<i32>` as argument
 fn fill_vec() -> Vec<i32> {
-    let mut vec = vec;
+    let mut vec = Vec::new();
 
     vec.push(22);
     vec.push(44);
diff --git a/exercises/move_semantics/move_semantics5.rs b/exercises/move_semantics/move_semantics5.rs
index 36eae127..ab04f4c7 100644
--- a/exercises/move_semantics/move_semantics5.rs
+++ b/exercises/move_semantics/move_semantics5.rs
@@ -3,13 +3,11 @@
 // adding, changing or removing any of them.
 // Execute `rustlings hint move_semantics5` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let mut x = 100;
     let y = &mut x;
-    let z = &mut x;
     *y += 100;
+    let z = &mut x;
     *z += 1000;
     assert_eq!(x, 1200);
 }
diff --git a/exercises/move_semantics/move_semantics6.rs b/exercises/move_semantics/move_semantics6.rs
index eb52a848..34d9e83e 100644
--- a/exercises/move_semantics/move_semantics6.rs
+++ b/exercises/move_semantics/move_semantics6.rs
@@ -2,24 +2,22 @@
 // Execute `rustlings hint move_semantics6` or use the `hint` watch subcommand for a hint.
 // You can't change anything except adding or removing references.
 
-// I AM NOT DONE
-
 fn main() {
     let data = "Rust is great!".to_string();
 
-    get_char(data);
+    get_char(&data);
 
-    string_uppercase(&data);
+    string_uppercase(data);
 }
 
 // Should not take ownership
-fn get_char(data: String) -> char {
+fn get_char(data: &str) -> char {
     data.chars().last().unwrap()
 }
 
 // Should take ownership
-fn string_uppercase(mut data: &String) {
-    data = &data.to_uppercase();
+fn string_uppercase(mut data: String) {
+    data = data.to_uppercase();
 
     println!("{}", data);
 }
diff --git a/exercises/options/options1.rs b/exercises/options/options1.rs
index 038fb48e..8d1dc4eb 100644
--- a/exercises/options/options1.rs
+++ b/exercises/options/options1.rs
@@ -1,8 +1,6 @@
 // options1.rs
 // Execute `rustlings hint options1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 // you can modify anything EXCEPT for this function's signature
 fn print_number(maybe_number: Option<u16>) {
     println!("printing: {}", maybe_number.unwrap());
@@ -14,7 +12,11 @@ fn print_number(maybe_number: Option<u16>) {
 // TODO: Return an Option!
 fn maybe_icecream(time_of_day: u16) -> Option<u16> {
     // We use the 24-hour system here, so 10PM is a value of 22
-    ???
+    if time_of_day < 22 {
+        Some(5)
+    } else {
+        None
+    }
 }
 
 #[cfg(test)]
@@ -31,7 +33,7 @@ mod tests {
     #[test]
     fn raw_value() {
         // TODO: Fix this test. How do you get at the value contained in the Option?
-        let icecreams = maybe_icecream(12);
+        let icecreams = maybe_icecream(12).unwrap();
         assert_eq!(icecreams, 5);
     }
 }
diff --git a/exercises/options/options2.rs b/exercises/options/options2.rs
index 75b66a37..b0061723 100644
--- a/exercises/options/options2.rs
+++ b/exercises/options/options2.rs
@@ -1,12 +1,10 @@
 // options2.rs
 // Execute `rustlings hint options2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let optional_word = Some(String::from("rustlings"));
     // TODO: Make this an if let statement whose value is "Some" type
-    word = optional_word {
+    if let Some(word) = optional_word {
         println!("The word is: {}", word);
     } else {
         println!("The optional word doesn't contain anything");
@@ -19,7 +17,7 @@ fn main() {
 
     // TODO: make this a while let statement - remember that vector.pop also adds another layer of Option<T>
     // You can stack `Option<T>`'s into while let and if let
-    integer = optional_integers_vec.pop() {
-        println!("current value: {}", integer);
+    while let Some(integer) = optional_integers_vec.pop() {
+        println!("current value: {}", integer.unwrap());
     }
 }
diff --git a/exercises/options/options3.rs b/exercises/options/options3.rs
index 3f995c52..1dd0b374 100644
--- a/exercises/options/options3.rs
+++ b/exercises/options/options3.rs
@@ -1,8 +1,6 @@
 // options3.rs
 // Execute `rustlings hint options3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 struct Point {
     x: i32,
     y: i32,
@@ -12,7 +10,7 @@ fn main() {
     let y: Option<Point> = Some(Point { x: 100, y: 200 });
 
     match y {
-        Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),
+        Some(ref p) => println!("Co-ordinates are {},{} ", p.x, p.y),
         _ => println!("no match"),
     }
     y; // Fix without deleting this line.
diff --git a/exercises/primitive_types/primitive_types1.rs b/exercises/primitive_types/primitive_types1.rs
index 09121392..7685d4fb 100644
--- a/exercises/primitive_types/primitive_types1.rs
+++ b/exercises/primitive_types/primitive_types1.rs
@@ -2,8 +2,6 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
-// I AM NOT DONE
-
 fn main() {
     // Booleans (`bool`)
 
@@ -12,7 +10,8 @@ fn main() {
         println!("Good morning!");
     }
 
-    let // Finish the rest of this line like the example! Or make it be false!
+    let is_evening = false;
+    // Finish the rest of this line like the example! Or make it be false!
     if is_evening {
         println!("Good evening!");
     }
diff --git a/exercises/primitive_types/primitive_types2.rs b/exercises/primitive_types/primitive_types2.rs
index 8730baab..864ec8a9 100644
--- a/exercises/primitive_types/primitive_types2.rs
+++ b/exercises/primitive_types/primitive_types2.rs
@@ -2,8 +2,6 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
-// I AM NOT DONE
-
 fn main() {
     // Characters (`char`)
 
@@ -18,9 +16,9 @@ fn main() {
         println!("Neither alphabetic nor numeric!");
     }
 
-    let // Finish this line like the example! What's your favorite character?
-    // Try a letter, try a number, try a special character, try a character
-    // from a different language than your own, try an emoji!
+    let your_character = '你'; // Finish this line like the example! What's your favorite character?
+                               // Try a letter, try a number, try a special character, try a character
+                               // from a different language than your own, try an emoji!
     if your_character.is_alphabetic() {
         println!("Alphabetical!");
     } else if your_character.is_numeric() {
diff --git a/exercises/primitive_types/primitive_types3.rs b/exercises/primitive_types/primitive_types3.rs
index fa7d019a..8343d336 100644
--- a/exercises/primitive_types/primitive_types3.rs
+++ b/exercises/primitive_types/primitive_types3.rs
@@ -2,10 +2,8 @@
 // Create an array with at least 100 elements in it where the ??? is.
 // Execute `rustlings hint primitive_types3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let a = ???
+    let a = [0; 100];
 
     if a.len() >= 100 {
         println!("Wow, that's a big array!");
diff --git a/exercises/primitive_types/primitive_types4.rs b/exercises/primitive_types/primitive_types4.rs
index 71fa243c..e3371784 100644
--- a/exercises/primitive_types/primitive_types4.rs
+++ b/exercises/primitive_types/primitive_types4.rs
@@ -2,13 +2,11 @@
 // Get a slice out of Array a where the ??? is so that the test passes.
 // Execute `rustlings hint primitive_types4` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[test]
 fn slice_out_of_array() {
     let a = [1, 2, 3, 4, 5];
 
-    let nice_slice = ???
+    let nice_slice = &a[1..4];
 
     assert_eq!([2, 3, 4], nice_slice)
 }
diff --git a/exercises/primitive_types/primitive_types5.rs b/exercises/primitive_types/primitive_types5.rs
index 4fd9141f..5cba3c15 100644
--- a/exercises/primitive_types/primitive_types5.rs
+++ b/exercises/primitive_types/primitive_types5.rs
@@ -2,11 +2,9 @@
 // Destructure the `cat` tuple so that the println will work.
 // Execute `rustlings hint primitive_types5` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let cat = ("Furry McFurson", 3.5);
-    let /* your pattern here */ = cat;
+    let (name, age) = cat;
 
     println!("{} is {} years old.", name, age);
 }
diff --git a/exercises/primitive_types/primitive_types6.rs b/exercises/primitive_types/primitive_types6.rs
index ddf8b423..4d614e57 100644
--- a/exercises/primitive_types/primitive_types6.rs
+++ b/exercises/primitive_types/primitive_types6.rs
@@ -3,14 +3,11 @@
 // You can put the expression for the second element where ??? is so that the test passes.
 // Execute `rustlings hint primitive_types6` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[test]
 fn indexing_tuple() {
     let numbers = (1, 2, 3);
     // Replace below ??? with the tuple indexing syntax.
-    let second = ???;
+    let second = numbers.1;
 
-    assert_eq!(2, second,
-        "This is not the 2nd number in the tuple!")
+    assert_eq!(2, second, "This is not the 2nd number in the tuple!")
 }
diff --git a/exercises/quiz1.rs b/exercises/quiz1.rs
index 8d05b110..3900f05c 100644
--- a/exercises/quiz1.rs
+++ b/exercises/quiz1.rs
@@ -8,10 +8,14 @@
 // more than 40 at once, each apple only costs 1! Write a function that calculates
 // the price of an order of apples given the quantity bought. No hints this time!
 
-// I AM NOT DONE
-
 // Put your function here!
-// fn calculate_price_of_apples {
+fn calculate_price_of_apples(num: i32) -> i32 {
+    if num <= 40 {
+        num * 2
+    } else {
+        num
+    }
+}
 
 // Don't modify this function!
 #[test]
diff --git a/exercises/quiz2.rs b/exercises/quiz2.rs
index f7437fd2..8c2eca30 100644
--- a/exercises/quiz2.rs
+++ b/exercises/quiz2.rs
@@ -18,8 +18,6 @@
 // - The output element is going to be a Vector of strings.
 // Execute `rustlings hint quiz2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub enum Command {
     Uppercase,
     Trim,
@@ -30,11 +28,18 @@ mod my_module {
     use super::Command;
 
     // TODO: Complete the function signature!
-    pub fn transformer(input: ???) -> ??? {
+    pub fn transformer(input: Vec<(String, Command)>) -> Vec<String> {
         // TODO: Complete the output declaration!
-        let mut output: ??? = vec![];
-        for (string, command) in input.iter() {
+        let mut output = vec![];
+        for (string, command) in input.into_iter() {
             // TODO: Complete the function body. You can do it!
+            match command {
+                Command::Uppercase => output.push(string.to_uppercase()),
+                Command::Trim => output.push(string.trim().to_string()),
+                Command::Append(num) => {
+                    output.push(format!("{}bar", string.repeat(num)));
+                }
+            }
         }
         output
     }
@@ -43,7 +48,7 @@ mod my_module {
 #[cfg(test)]
 mod tests {
     // TODO: What to we have to import to have `transformer` in scope?
-    use ???;
+    use super::my_module::transformer;
     use super::Command;
 
     #[test]
diff --git a/exercises/quiz3.rs b/exercises/quiz3.rs
index 15dc4699..e9e37490 100644
--- a/exercises/quiz3.rs
+++ b/exercises/quiz3.rs
@@ -14,18 +14,20 @@
 
 // Execute `rustlings hint quiz3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
+use std::fmt::Display;
 
-pub struct ReportCard {
-    pub grade: f32,
+pub struct ReportCard<T> {
+    pub grade: T,
     pub student_name: String,
     pub student_age: u8,
 }
 
-impl ReportCard {
+impl<T: Display> ReportCard<T> {
     pub fn print(&self) -> String {
-        format!("{} ({}) - achieved a grade of {}",
-            &self.student_name, &self.student_age, &self.grade)
+        format!(
+            "{} ({}) - achieved a grade of {}",
+            &self.student_name, &self.student_age, &self.grade
+        )
     }
 }
 
@@ -50,7 +52,7 @@ mod tests {
     fn generate_alphabetic_report_card() {
         // TODO: Make sure to change the grade here after you finish the exercise.
         let report_card = ReportCard {
-            grade: 2.1,
+            grade: "A+",
             student_name: "Gary Plotter".to_string(),
             student_age: 11,
         };
diff --git a/exercises/standard_library_types/arc1.rs b/exercises/standard_library_types/arc1.rs
index 93a27036..6e33ef54 100644
--- a/exercises/standard_library_types/arc1.rs
+++ b/exercises/standard_library_types/arc1.rs
@@ -12,25 +12,22 @@
 // Because we are using threads, our values need to be thread-safe.  Therefore,
 // we are using Arc.  We need to make a change in each of the two TODOs.
 
-
 // Make this code compile by filling in a value for `shared_numbers` where the
 // first TODO comment is, and create an initial binding for `child_numbers`
 // where the second TODO comment is. Try not to create any copies of the `numbers` Vec!
 // Execute `rustlings hint arc1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #![forbid(unused_imports)] // Do not change this, (or the next) line.
 use std::sync::Arc;
 use std::thread;
 
 fn main() {
     let numbers: Vec<_> = (0..100u32).collect();
-    let shared_numbers = // TODO
+    let shared_numbers = Arc::new(numbers);
     let mut joinhandles = Vec::new();
 
     for offset in 0..8 {
-        let child_numbers = // TODO
+        let child_numbers = Arc::clone(&shared_numbers); // TODO
         joinhandles.push(thread::spawn(move || {
             let sum: u32 = child_numbers.iter().filter(|n| *n % 8 == offset).sum();
             println!("Sum of offset {} is {}", offset, sum);
diff --git a/exercises/standard_library_types/box1.rs b/exercises/standard_library_types/box1.rs
index 9d9237c1..2f8f2f96 100644
--- a/exercises/standard_library_types/box1.rs
+++ b/exercises/standard_library_types/box1.rs
@@ -16,11 +16,9 @@
 //
 // Execute `rustlings hint box1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[derive(PartialEq, Debug)]
 pub enum List {
-    Cons(i32, List),
+    Cons(i32, Box<List>),
     Nil,
 }
 
@@ -33,11 +31,11 @@ fn main() {
 }
 
 pub fn create_empty_list() -> List {
-    unimplemented!()
+    List::Nil
 }
 
 pub fn create_non_empty_list() -> List {
-    unimplemented!()
+    List::Cons(10, Box::new(List::Nil))
 }
 
 #[cfg(test)]
diff --git a/exercises/standard_library_types/iterators1.rs b/exercises/standard_library_types/iterators1.rs
index 0379c6bb..626a8524 100644
--- a/exercises/standard_library_types/iterators1.rs
+++ b/exercises/standard_library_types/iterators1.rs
@@ -8,17 +8,15 @@
 //
 // Execute `rustlings hint iterators1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-fn main () {
+fn main() {
     let my_fav_fruits = vec!["banana", "custard apple", "avocado", "peach", "raspberry"];
 
-    let mut my_iterable_fav_fruits = ???;   // TODO: Step 1
+    let mut my_iterable_fav_fruits = my_fav_fruits.iter(); // TODO: Step 1
 
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"banana"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 2
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"custard apple")); // TODO: Step 2
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"avocado"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 3
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"peach")); // TODO: Step 3
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"raspberry"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 4
+    assert_eq!(my_iterable_fav_fruits.next(), None); // TODO: Step 4
 }
diff --git a/exercises/standard_library_types/iterators2.rs b/exercises/standard_library_types/iterators2.rs
index 29c53afb..7e5512d9 100644
--- a/exercises/standard_library_types/iterators2.rs
+++ b/exercises/standard_library_types/iterators2.rs
@@ -3,8 +3,6 @@
 // can offer. Follow the steps to complete the exercise.
 // Execute `rustlings hint iterators2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 // Step 1.
 // Complete the `capitalize_first` function.
 // "hello" -> "Hello"
@@ -12,7 +10,7 @@ pub fn capitalize_first(input: &str) -> String {
     let mut c = input.chars();
     match c.next() {
         None => String::new(),
-        Some(first) => ???,
+        Some(first) => first.to_uppercase().collect::<String>() + c.as_str(),
     }
 }
 
@@ -21,7 +19,7 @@ pub fn capitalize_first(input: &str) -> String {
 // Return a vector of strings.
 // ["hello", "world"] -> ["Hello", "World"]
 pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
-    vec![]
+    words.into_iter().map(|x| capitalize_first(x)).collect()
 }
 
 // Step 3.
@@ -29,7 +27,7 @@ pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
 // Return a single string.
 // ["hello", " ", "world"] -> "Hello World"
 pub fn capitalize_words_string(words: &[&str]) -> String {
-    String::new()
+    capitalize_words_vector(words).join("")
 }
 
 #[cfg(test)]
diff --git a/exercises/standard_library_types/iterators3.rs b/exercises/standard_library_types/iterators3.rs
index c97a6258..20ed01f7 100644
--- a/exercises/standard_library_types/iterators3.rs
+++ b/exercises/standard_library_types/iterators3.rs
@@ -6,8 +6,6 @@
 //    list_of_results functions.
 // Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[derive(Debug, PartialEq, Eq)]
 pub enum DivisionError {
     NotDivisible(NotDivisibleError),
@@ -23,21 +21,30 @@ pub struct NotDivisibleError {
 // Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
 // Otherwise, return a suitable error.
 pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
-    todo!();
+    if b == 0 {
+        Err(DivisionError::DivideByZero)
+    } else if a % b == 0 {
+        Ok(a / b)
+    } else {
+        Err(DivisionError::NotDivisible(NotDivisibleError {
+            dividend: a,
+            divisor: b,
+        }))
+    }
 }
 
 // Complete the function and return a value of the correct type so the test passes.
 // Desired output: Ok([1, 11, 1426, 3])
-fn result_with_list() -> () {
+fn result_with_list() -> Result<Vec<i32>, DivisionError> {
     let numbers = vec![27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    numbers.into_iter().map(|n| divide(n, 27)).collect()
 }
 
 // Complete the function and return a value of the correct type so the test passes.
 // Desired output: [Ok(1), Ok(11), Ok(1426), Ok(3)]
-fn list_of_results() -> () {
+fn list_of_results() -> Vec<Result<i32, DivisionError>> {
     let numbers = vec![27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    numbers.into_iter().map(|n| divide(n, 27)).collect()
 }
 
 #[cfg(test)]
diff --git a/exercises/standard_library_types/iterators4.rs b/exercises/standard_library_types/iterators4.rs
index a02470ec..bef3fb57 100644
--- a/exercises/standard_library_types/iterators4.rs
+++ b/exercises/standard_library_types/iterators4.rs
@@ -1,9 +1,7 @@
 // iterators4.rs
 // Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-pub fn factorial(num: u64) -> u64 {
+pub fn factorial(mut num: u64) -> u64 {
     // Complete this function to return the factorial of num
     // Do not use:
     // - return
@@ -13,6 +11,7 @@ pub fn factorial(num: u64) -> u64 {
     // For an extra challenge, don't use:
     // - recursion
     // Execute `rustlings hint iterators4` for hints.
+    (1..=num).fold(1, |sum, v| sum * v)
 }
 
 #[cfg(test)]
diff --git a/exercises/standard_library_types/iterators5.rs b/exercises/standard_library_types/iterators5.rs
index 0593d123..bbf75c9d 100644
--- a/exercises/standard_library_types/iterators5.rs
+++ b/exercises/standard_library_types/iterators5.rs
@@ -10,8 +10,6 @@
 //
 // Make the code compile and the tests pass.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 #[derive(Clone, Copy, PartialEq, Eq)]
@@ -34,7 +32,7 @@ fn count_for(map: &HashMap<String, Progress>, value: Progress) -> usize {
 fn count_iterator(map: &HashMap<String, Progress>, value: Progress) -> usize {
     // map is a hashmap with String keys and Progress values.
     // map = { "variables1": Complete, "from_str": None, ... }
-    todo!();
+    map.values().into_iter().filter(|&v| v == &value).count()
 }
 
 fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
@@ -53,7 +51,10 @@ fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Pr
     // collection is a slice of hashmaps.
     // collection = [{ "variables1": Complete, "from_str": None, ... },
     //     { "variables2": Complete, ... }, ... ]
-    todo!();
+    collection
+        .into_iter()
+        .map(|x| count_iterator(&x, value))
+        .sum()
 }
 
 #[cfg(test)]
diff --git a/exercises/strings/strings1.rs b/exercises/strings/strings1.rs
index 0de86a1d..1211c9ea 100644
--- a/exercises/strings/strings1.rs
+++ b/exercises/strings/strings1.rs
@@ -2,13 +2,11 @@
 // Make me compile without changing the function signature!
 // Execute `rustlings hint strings1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let answer = current_favorite_color();
     println!("My current favorite color is {}", answer);
 }
 
 fn current_favorite_color() -> String {
-    "blue"
+    String::from("blue")
 }
diff --git a/exercises/strings/strings2.rs b/exercises/strings/strings2.rs
index 0c48ec95..22e8986e 100644
--- a/exercises/strings/strings2.rs
+++ b/exercises/strings/strings2.rs
@@ -2,11 +2,9 @@
 // Make me compile without changing the function signature!
 // Execute `rustlings hint strings2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let word = String::from("green"); // Try not changing this line :)
-    if is_a_color_word(word) {
+    if is_a_color_word(&word) {
         println!("That is a color word I know!");
     } else {
         println!("That is not a color word I know.");
diff --git a/exercises/strings/strings3.rs b/exercises/strings/strings3.rs
index 9e25d307..82b24aac 100644
--- a/exercises/strings/strings3.rs
+++ b/exercises/strings/strings3.rs
@@ -1,21 +1,19 @@
 // strings3.rs
 // Execute `rustlings hint strings3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn trim_me(input: &str) -> String {
     // TODO: Remove whitespace from the end of a string!
-    ???
+    input.trim().to_string()
 }
 
 fn compose_me(input: &str) -> String {
     // TODO: Add " world!" to the string! There's multiple ways to do this!
-    ???
+    format!("{input} world!")
 }
 
 fn replace_me(input: &str) -> String {
     // TODO: Replace "cars" in the string with "balloons"!
-    ???
+    input.replace("cars", "balloons")
 }
 
 #[cfg(test)]
@@ -37,7 +35,13 @@ mod tests {
 
     #[test]
     fn replace_a_string() {
-        assert_eq!(replace_me("I think cars are cool"), "I think balloons are cool");
-        assert_eq!(replace_me("I love to look at cars"), "I love to look at balloons");
+        assert_eq!(
+            replace_me("I think cars are cool"),
+            "I think balloons are cool"
+        );
+        assert_eq!(
+            replace_me("I love to look at cars"),
+            "I love to look at balloons"
+        );
     }
 }
diff --git a/exercises/strings/strings4.rs b/exercises/strings/strings4.rs
index c410b562..0205f9c3 100644
--- a/exercises/strings/strings4.rs
+++ b/exercises/strings/strings4.rs
@@ -6,8 +6,6 @@
 // before the parentheses on each line. If you're right, it will compile!
 // No hints this time!
 
-// I AM NOT DONE
-
 fn string_slice(arg: &str) {
     println!("{}", arg);
 }
@@ -16,14 +14,14 @@ fn string(arg: String) {
 }
 
 fn main() {
-    ???("blue");
-    ???("red".to_string());
-    ???(String::from("hi"));
-    ???("rust is fun!".to_owned());
-    ???("nice weather".into());
-    ???(format!("Interpolation {}", "Station"));
-    ???(&String::from("abc")[0..1]);
-    ???("  hello there ".trim());
-    ???("Happy Monday!".to_string().replace("Mon", "Tues"));
-    ???("mY sHiFt KeY iS sTiCkY".to_lowercase());
+    string_slice("blue");
+    string("red".to_string());
+    string(String::from("hi"));
+    string("rust is fun!".to_owned());
+    string("nice weather".into());
+    string(format!("Interpolation {}", "Station"));
+    string_slice(&String::from("abc")[0..1]);
+    string_slice("  hello there ".trim());
+    string("Happy Monday!".to_string().replace("Mon", "Tues"));
+    string("mY sHiFt KeY iS sTiCkY".to_lowercase());
 }
diff --git a/exercises/structs/structs1.rs b/exercises/structs/structs1.rs
index 0d91c469..a78ecf26 100644
--- a/exercises/structs/structs1.rs
+++ b/exercises/structs/structs1.rs
@@ -2,13 +2,14 @@
 // Address all the TODOs to make the tests pass!
 // Execute `rustlings hint structs1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 struct ColorClassicStruct {
+    red: i32,
+    green: i32,
+    blue: i32,
     // TODO: Something goes here
 }
 
-struct ColorTupleStruct(/* TODO: Something goes here */);
+struct ColorTupleStruct(i32, i32, i32);
 
 #[derive(Debug)]
 struct UnitLikeStruct;
@@ -20,8 +21,11 @@ mod tests {
     #[test]
     fn classic_c_structs() {
         // TODO: Instantiate a classic c struct!
-        // let green =
-
+        let green = ColorClassicStruct {
+            red: 0,
+            green: 255,
+            blue: 0,
+        };
         assert_eq!(green.red, 0);
         assert_eq!(green.green, 255);
         assert_eq!(green.blue, 0);
@@ -30,7 +34,7 @@ mod tests {
     #[test]
     fn tuple_structs() {
         // TODO: Instantiate a tuple struct!
-        // let green =
+        let green = (0, 255, 0);
 
         assert_eq!(green.0, 0);
         assert_eq!(green.1, 255);
@@ -40,7 +44,7 @@ mod tests {
     #[test]
     fn unit_structs() {
         // TODO: Instantiate a unit-like struct!
-        // let unit_like_struct =
+        let unit_like_struct = UnitLikeStruct {};
         let message = format!("{:?}s are fun!", unit_like_struct);
 
         assert_eq!(message, "UnitLikeStructs are fun!");
diff --git a/exercises/structs/structs2.rs b/exercises/structs/structs2.rs
index 32e311fa..7cb860a3 100644
--- a/exercises/structs/structs2.rs
+++ b/exercises/structs/structs2.rs
@@ -2,8 +2,6 @@
 // Address all the TODOs to make the tests pass!
 // Execute `rustlings hint structs2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[derive(Debug)]
 struct Order {
     name: String,
@@ -35,7 +33,11 @@ mod tests {
     fn your_order() {
         let order_template = create_order_template();
         // TODO: Create your own order using the update syntax and template above!
-        // let your_order =
+        let your_order = Order {
+            name: String::from("Hacker in Rust"),
+            count: 1,
+            ..order_template
+        };
         assert_eq!(your_order.name, "Hacker in Rust");
         assert_eq!(your_order.year, order_template.year);
         assert_eq!(your_order.made_by_phone, order_template.made_by_phone);
diff --git a/exercises/structs/structs3.rs b/exercises/structs/structs3.rs
index 0b3615f4..0177e5a4 100644
--- a/exercises/structs/structs3.rs
+++ b/exercises/structs/structs3.rs
@@ -4,8 +4,6 @@
 // Make the code compile and the tests pass!
 // Execute `rustlings hint structs3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[derive(Debug)]
 struct Package {
     sender_country: String,
@@ -26,12 +24,12 @@ impl Package {
         }
     }
 
-    fn is_international(&self) -> ??? {
-        // Something goes here...
+    fn is_international(&self) -> bool {
+        self.sender_country != self.recipient_country
     }
 
-    fn get_fees(&self, cents_per_gram: i32) -> ??? {
-        // Something goes here...
+    fn get_fees(&self, cents_per_gram: i32) -> i32 {
+        self.weight_in_grams * cents_per_gram
     }
 }
 
diff --git a/exercises/tests/tests1.rs b/exercises/tests/tests1.rs
index 8b6ea374..479f182b 100644
--- a/exercises/tests/tests1.rs
+++ b/exercises/tests/tests1.rs
@@ -7,12 +7,10 @@
 // pass! Make the test fail!
 // Execute `rustlings hint tests1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[cfg(test)]
 mod tests {
     #[test]
     fn you_can_assert() {
-        assert!();
+        assert!(true);
     }
 }
diff --git a/exercises/tests/tests2.rs b/exercises/tests/tests2.rs
index a5ac15b1..e0d59256 100644
--- a/exercises/tests/tests2.rs
+++ b/exercises/tests/tests2.rs
@@ -3,12 +3,10 @@
 // pass! Make the test fail!
 // Execute `rustlings hint tests2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[cfg(test)]
 mod tests {
     #[test]
     fn you_can_assert_eq() {
-        assert_eq!();
+        assert_eq!(1, 1);
     }
 }
diff --git a/exercises/tests/tests3.rs b/exercises/tests/tests3.rs
index 196a81a0..24028a59 100644
--- a/exercises/tests/tests3.rs
+++ b/exercises/tests/tests3.rs
@@ -4,8 +4,6 @@
 // we expect to get when we call `is_even(5)`.
 // Execute `rustlings hint tests3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0
 }
@@ -16,11 +14,11 @@ mod tests {
 
     #[test]
     fn is_true_when_even() {
-        assert!();
+        assert!(is_even(2));
     }
 
     #[test]
     fn is_false_when_odd() {
-        assert!();
+        assert!(!is_even(1));
     }
 }
diff --git a/exercises/threads/threads1.rs b/exercises/threads/threads1.rs
index e59f4ce4..fa9e27ca 100644
--- a/exercises/threads/threads1.rs
+++ b/exercises/threads/threads1.rs
@@ -2,30 +2,26 @@
 // Execute `rustlings hint threads1` or use the `hint` watch subcommand for a hint.
 // This program should wait until all the spawned threads have finished before exiting.
 
-// I AM NOT DONE
-
 use std::thread;
 use std::time::Duration;
 
-
 fn main() {
-
     let mut handles = vec![];
     for i in 0..10 {
-        thread::spawn(move || {
+        handles.push(thread::spawn(move || {
             thread::sleep(Duration::from_millis(250));
             println!("thread {} is complete", i);
-        });
+        }));
     }
 
     let mut completed_threads = 0;
     for handle in handles {
         // TODO: a struct is returned from thread::spawn, can you use it?
+        handle.join().unwrap();
         completed_threads += 1;
     }
 
     if completed_threads != 10 {
         panic!("Oh no! All the spawned threads did not finish!");
     }
-    
 }
diff --git a/exercises/threads/threads2.rs b/exercises/threads/threads2.rs
index d0f8578f..ee004693 100644
--- a/exercises/threads/threads2.rs
+++ b/exercises/threads/threads2.rs
@@ -3,9 +3,7 @@
 // Building on the last exercise, we want all of the threads to complete their work but this time
 // the spawned threads need to be in charge of updating a shared value: JobStatus.jobs_completed
 
-// I AM NOT DONE
-
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use std::thread;
 use std::time::Duration;
 
@@ -14,13 +12,14 @@ struct JobStatus {
 }
 
 fn main() {
-    let status = Arc::new(JobStatus { jobs_completed: 0 });
+    let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));
     let mut handles = vec![];
     for _ in 0..10 {
         let status_shared = status.clone();
         let handle = thread::spawn(move || {
             thread::sleep(Duration::from_millis(250));
             // TODO: You must take an action before you update a shared value
+            let mut status_shared = status_shared.lock().unwrap();
             status_shared.jobs_completed += 1;
         });
         handles.push(handle);
@@ -29,6 +28,6 @@ fn main() {
         handle.join().unwrap();
         // TODO: Print the value of the JobStatus.jobs_completed. Did you notice anything
         // interesting in the output? Do you have to 'join' on all the handles?
-        println!("jobs completed {}", ???);
+        println!("jobs completed {}", status.lock().unwrap().jobs_completed);
     }
 }
diff --git a/exercises/threads/threads3.rs b/exercises/threads/threads3.rs
index 27e99088..60fa114b 100644
--- a/exercises/threads/threads3.rs
+++ b/exercises/threads/threads3.rs
@@ -1,10 +1,8 @@
 // threads3.rs
 // Execute `rustlings hint threads3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::sync::mpsc;
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use std::thread;
 use std::time::Duration;
 
@@ -24,23 +22,27 @@ impl Queue {
     }
 }
 
-fn send_tx(q: Queue, tx: mpsc::Sender<u32>) -> () {
+fn send_tx(q: Queue, tx: Arc<Mutex<mpsc::Sender<u32>>>) -> () {
     let qc = Arc::new(q);
     let qc1 = qc.clone();
     let qc2 = qc.clone();
 
+    let tx1 = tx.clone();
     thread::spawn(move || {
         for val in &qc1.first_half {
             println!("sending {:?}", val);
-            tx.send(*val).unwrap();
+            let tx1 = tx1.lock().unwrap();
+            tx1.send(*val).unwrap();
             thread::sleep(Duration::from_secs(1));
         }
     });
 
+    let tx2 = tx.clone();
     thread::spawn(move || {
         for val in &qc2.second_half {
             println!("sending {:?}", val);
-            tx.send(*val).unwrap();
+            let tx2 = tx2.lock().unwrap();
+            tx2.send(*val).unwrap();
             thread::sleep(Duration::from_secs(1));
         }
     });
@@ -51,6 +53,8 @@ fn main() {
     let queue = Queue::new();
     let queue_length = queue.length;
 
+    let tx = Arc::new(Mutex::new(tx));
+
     send_tx(queue, tx);
 
     let mut total_received: u32 = 0;
diff --git a/exercises/traits/traits1.rs b/exercises/traits/traits1.rs
index 5b9d8d50..dba90952 100644
--- a/exercises/traits/traits1.rs
+++ b/exercises/traits/traits1.rs
@@ -9,14 +9,16 @@
 // implementing this trait.
 // Execute `rustlings hint traits1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 trait AppendBar {
     fn append_bar(self) -> Self;
 }
 
 impl AppendBar for String {
     //Add your code here
+
+    fn append_bar(self) -> Self {
+        format!("{self}Bar")
+    }
 }
 
 fn main() {
diff --git a/exercises/traits/traits2.rs b/exercises/traits/traits2.rs
index 708bb19a..db0a6bca 100644
--- a/exercises/traits/traits2.rs
+++ b/exercises/traits/traits2.rs
@@ -11,13 +11,17 @@
 // you can do this!
 // Execute `rustlings hint traits2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 trait AppendBar {
     fn append_bar(self) -> Self;
 }
 
 //TODO: Add your code here
+impl AppendBar for Vec<String> {
+    fn append_bar(mut self) -> Self {
+        self.push("Bar".into());
+        self
+    }
+}
 
 #[cfg(test)]
 mod tests {
diff --git a/exercises/traits/traits3.rs b/exercises/traits/traits3.rs
index 6d2fd6c3..adc9ebc4 100644
--- a/exercises/traits/traits3.rs
+++ b/exercises/traits/traits3.rs
@@ -7,10 +7,10 @@
 // Consider what you can add to the Licensed trait.
 // Execute `rustlings hint traits3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub trait Licensed {
-    fn licensing_info(&self) -> String;
+    fn licensing_info(&self) -> String {
+        "Some information".into()
+    }
 }
 
 struct SomeSoftware {
diff --git a/exercises/traits/traits4.rs b/exercises/traits/traits4.rs
index 280aaade..0808d9f5 100644
--- a/exercises/traits/traits4.rs
+++ b/exercises/traits/traits4.rs
@@ -4,8 +4,6 @@
 // Don't change any line other than 21.
 // Execute `rustlings hint traits4` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub trait Licensed {
     fn licensing_info(&self) -> String {
         "some information".to_string()
@@ -19,7 +17,7 @@ struct OtherSoftware {}
 impl Licensed for SomeSoftware {}
 impl Licensed for OtherSoftware {}
 
-fn compare_license_types(software: ??, software_two: ??) -> bool {
+fn compare_license_types(software: &impl Licensed, software_two: &impl Licensed) -> bool {
     software.licensing_info() == software_two.licensing_info()
 }
 
diff --git a/exercises/traits/traits5.rs b/exercises/traits/traits5.rs
index 290c0479..39d9242b 100644
--- a/exercises/traits/traits5.rs
+++ b/exercises/traits/traits5.rs
@@ -4,8 +4,6 @@
 // Don't change any line other than 27.
 // Execute `rustlings hint traits5` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub trait SomeTrait {
     fn some_function(&self) -> bool {
         true
@@ -25,7 +23,10 @@ struct SomeStruct {
 impl SomeTrait for SomeStruct {}
 impl OtherTrait for SomeStruct {}
 
-fn some_func(item: ??) -> bool {
+fn some_func<T>(item: &T) -> bool
+where
+    T: SomeTrait + OtherTrait,
+{
     item.some_function() && item.other_function()
 }
 
diff --git a/exercises/variables/variables1.rs b/exercises/variables/variables1.rs
index f4d182ac..84de9fdc 100644
--- a/exercises/variables/variables1.rs
+++ b/exercises/variables/variables1.rs
@@ -2,9 +2,7 @@
 // Make me compile!
 // Execute `rustlings hint variables1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    x = 5;
+    let x = 5;
     println!("x has the value {}", x);
 }
diff --git a/exercises/variables/variables2.rs b/exercises/variables/variables2.rs
index 641aeb8e..ea8b1076 100644
--- a/exercises/variables/variables2.rs
+++ b/exercises/variables/variables2.rs
@@ -1,10 +1,8 @@
 // variables2.rs
 // Execute `rustlings hint variables2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let x;
+    let x = 10;
     if x == 10 {
         println!("x is ten!");
     } else {
diff --git a/exercises/variables/variables3.rs b/exercises/variables/variables3.rs
index 819b1bc7..619895fc 100644
--- a/exercises/variables/variables3.rs
+++ b/exercises/variables/variables3.rs
@@ -1,9 +1,7 @@
 // variables3.rs
 // Execute `rustlings hint variables3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let x: i32;
+    let x: i32 = 10;
     println!("Number {}", x);
 }
diff --git a/exercises/variables/variables4.rs b/exercises/variables/variables4.rs
index 54491b0a..8c2ddd6d 100644
--- a/exercises/variables/variables4.rs
+++ b/exercises/variables/variables4.rs
@@ -1,10 +1,8 @@
 // variables4.rs
 // Execute `rustlings hint variables4` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let x = 3;
+    let mut x = 3;
     println!("Number {}", x);
     x = 5; // don't change this line
     println!("Number {}", x);
diff --git a/exercises/variables/variables5.rs b/exercises/variables/variables5.rs
index 0e670d2a..1b9d9f48 100644
--- a/exercises/variables/variables5.rs
+++ b/exercises/variables/variables5.rs
@@ -1,11 +1,9 @@
 // variables5.rs
 // Execute `rustlings hint variables5` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let number = "T-H-R-E-E"; // don't change this line
     println!("Spell a Number : {}", number);
-    number = 3; // don't rename this variable
+    let number = 3; // don't rename this variable
     println!("Number plus two is : {}", number + 2);
 }
diff --git a/exercises/variables/variables6.rs b/exercises/variables/variables6.rs
index a8520122..e8314b28 100644
--- a/exercises/variables/variables6.rs
+++ b/exercises/variables/variables6.rs
@@ -1,9 +1,7 @@
 // variables6.rs
 // Execute `rustlings hint variables6` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-const NUMBER = 3;
+const NUMBER: i32 = 3;
 fn main() {
     println!("Number {}", NUMBER);
 }
diff --git a/exercises/vecs/vecs1.rs b/exercises/vecs/vecs1.rs
index 4e8c4cbb..9c448fa8 100644
--- a/exercises/vecs/vecs1.rs
+++ b/exercises/vecs/vecs1.rs
@@ -4,11 +4,9 @@
 // Make me compile and pass the test!
 // Execute `rustlings hint vecs1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn array_and_vec() -> ([i32; 4], Vec<i32>) {
     let a = [10, 20, 30, 40]; // a plain array
-    let v = // TODO: declare your vector here with the macro for vectors
+    let v = vec![10, 20, 30, 40];
 
     (a, v)
 }
diff --git a/exercises/vecs/vecs2.rs b/exercises/vecs/vecs2.rs
index 5bea09a2..673d6257 100644
--- a/exercises/vecs/vecs2.rs
+++ b/exercises/vecs/vecs2.rs
@@ -6,13 +6,11 @@
 //
 // Execute `rustlings hint vecs2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
     for i in v.iter_mut() {
         // TODO: Fill this up so that each element in the Vec `v` is
         // multiplied by 2.
-        ???
+        *i *= 2;
     }
 
     // At this point, `v` should be equal to [4, 8, 12, 16, 20].
@@ -20,11 +18,13 @@ fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
 }
 
 fn vec_map(v: &Vec<i32>) -> Vec<i32> {
-    v.iter().map(|num| {
-        // TODO: Do the same thing as above - but instead of mutating the
-        // Vec, you can just return the new number!
-        ???
-    }).collect()
+    v.iter()
+        .map(|num| {
+            // TODO: Do the same thing as above - but instead of mutating the
+            // Vec, you can just return the new number!
+            num * 2
+        })
+        .collect()
 }
 
 #[cfg(test)]
diff --git a/src/exercise.rs b/src/exercise.rs
index 4be3a2cc..188b59e6 100644
--- a/src/exercise.rs
+++ b/src/exercise.rs
@@ -154,7 +154,7 @@ path = "{}.rs""#,
                 Command::new("cargo")
                     .args(&["clippy", "--manifest-path", CLIPPY_CARGO_TOML_PATH])
                     .args(RUSTC_COLOR_ARGS)
-                    .args(&["--", "-D", "warnings","-D","clippy::float_cmp"])
+                    .args(&["--", "-D", "warnings", "-D", "clippy::float_cmp"])
                     .output()
             }
         }
diff --git a/src/main.rs b/src/main.rs
index 0ddb7331..159c7072 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -85,7 +85,6 @@ struct HintArgs {
 /// Enable rust-analyzer for exercises
 struct LspArgs {}
 
-
 #[derive(FromArgs, PartialEq, Debug)]
 #[argh(subcommand, name = "list")]
 /// Lists the exercises available in Rustlings
@@ -164,7 +163,9 @@ fn main() {
                     "Pending"
                 };
                 let solve_cond = {
-                    (e.looks_done() && subargs.solved) || (!e.looks_done() && subargs.unsolved) || (!subargs.solved && !subargs.unsolved)
+                    (e.looks_done() && subargs.solved)
+                        || (!e.looks_done() && subargs.unsolved)
+                        || (!subargs.solved && !subargs.unsolved)
                 };
                 if solve_cond && (filter_cond || subargs.filter.is_none()) {
                     let line = if subargs.paths {
@@ -212,7 +213,8 @@ fn main() {
         }
 
         Subcommands::Verify(_subargs) => {
-            verify(&exercises, (0, exercises.len()), verbose).unwrap_or_else(|_| std::process::exit(1));
+            verify(&exercises, (0, exercises.len()), verbose)
+                .unwrap_or_else(|_| std::process::exit(1));
         }
 
         Subcommands::Lsp(_subargs) => {
@@ -236,12 +238,18 @@ fn main() {
 
         Subcommands::Watch(_subargs) => match watch(&exercises, verbose) {
             Err(e) => {
-                println!("Error: Could not watch your progress. Error message was {:?}.", e);
+                println!(
+                    "Error: Could not watch your progress. Error message was {:?}.",
+                    e
+                );
                 println!("Most likely you've run out of disk space or your 'inotify limit' has been reached.");
                 std::process::exit(1);
             }
             Ok(WatchStatus::Finished) => {
-                println!("{emoji} All exercises completed! {emoji}", emoji = Emoji("🎉", "★"));
+                println!(
+                    "{emoji} All exercises completed! {emoji}",
+                    emoji = Emoji("🎉", "★")
+                );
                 println!("\n{}\n", FENISH_LINE);
             }
             Ok(WatchStatus::Unfinished) => {
@@ -252,8 +260,10 @@ fn main() {
     }
 }
 
-
-fn spawn_watch_shell(failed_exercise_hint: &Arc<Mutex<Option<String>>>, should_quit: Arc<AtomicBool>) {
+fn spawn_watch_shell(
+    failed_exercise_hint: &Arc<Mutex<Option<String>>>,
+    should_quit: Arc<AtomicBool>,
+) {
     let failed_exercise_hint = Arc::clone(failed_exercise_hint);
     println!("Welcome to watch mode! You can type 'help' to get an overview of the commands you can use here.");
     thread::spawn(move || loop {
@@ -290,16 +300,22 @@ fn spawn_watch_shell(failed_exercise_hint: &Arc<Mutex<Option<String>>>, should_q
 
 fn find_exercise<'a>(name: &str, exercises: &'a [Exercise]) -> &'a Exercise {
     if name.eq("next") {
-        exercises.iter().find(|e| !e.looks_done()).unwrap_or_else(|| {
-            println!("🎉 Congratulations! You have done all the exercises!");
-            println!("🔚 There are no more exercises to do next!");
-            std::process::exit(1)
-        })
+        exercises
+            .iter()
+            .find(|e| !e.looks_done())
+            .unwrap_or_else(|| {
+                println!("🎉 Congratulations! You have done all the exercises!");
+                println!("🔚 There are no more exercises to do next!");
+                std::process::exit(1)
+            })
     } else {
-        exercises.iter().find(|e| e.name == name).unwrap_or_else(|| {
-            println!("No exercise found for '{}'!", name);
-            std::process::exit(1)
-        })
+        exercises
+            .iter()
+            .find(|e| e.name == name)
+            .unwrap_or_else(|| {
+                println!("No exercise found for '{}'!", name);
+                std::process::exit(1)
+            })
     }
 }
 
@@ -337,8 +353,13 @@ fn watch(exercises: &[Exercise], verbose: bool) -> notify::Result<WatchStatus> {
                         let filepath = b.as_path().canonicalize().unwrap();
                         let pending_exercises = exercises
                             .iter()
-                            .find(|e| filepath.ends_with(&e.path)).into_iter()
-                            .chain(exercises.iter().filter(|e| !e.looks_done() && !filepath.ends_with(&e.path)));
+                            .find(|e| filepath.ends_with(&e.path))
+                            .into_iter()
+                            .chain(
+                                exercises
+                                    .iter()
+                                    .filter(|e| !e.looks_done() && !filepath.ends_with(&e.path)),
+                            );
                         let num_done = exercises.iter().filter(|e| e.looks_done()).count();
                         clear_screen();
                         match verify(pending_exercises, (num_done, exercises.len()), verbose) {
diff --git a/src/verify.rs b/src/verify.rs
index 6f877831..2d66f514 100644
--- a/src/verify.rs
+++ b/src/verify.rs
@@ -15,9 +15,10 @@ pub fn verify<'a>(
 ) -> Result<(), &'a Exercise> {
     let (num_done, total) = progress;
     let bar = ProgressBar::new(total as u64);
-    bar.set_style(ProgressStyle::default_bar()
-        .template("Progress: [{bar:60.green/red}] {pos}/{len}")
-        .progress_chars("#>-")
+    bar.set_style(
+        ProgressStyle::default_bar()
+            .template("Progress: [{bar:60.green/red}] {pos}/{len}")
+            .progress_chars("#>-"),
     );
     bar.set_position(num_done as u64);
     for exercise in exercises {
diff --git a/tests/integration_tests.rs b/tests/integration_tests.rs
index fc46b983..7202fd06 100644
--- a/tests/integration_tests.rs
+++ b/tests/integration_tests.rs
@@ -126,7 +126,7 @@ fn all_exercises_require_confirmation() {
     for exercise in glob("exercises/**/*.rs").unwrap() {
         let path = exercise.unwrap();
         if path.file_name().unwrap() == "mod.rs" {
-            continue
+            continue;
         }
         let source = {
             let mut file = File::open(&path).unwrap();