Solve collection exercises.

exercises/collections/hashmap1.rs

@@ -11,17 +11,17 @@
 // Execute the command `rustlings hint hashmap1` if you need
 // hints.
 
-// 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();
 
     // Two bananas are already given for you :)
     basket.insert(String::from("banana"), 2);
 
     // TODO: Put more fruits in your basket here.
+    basket.insert(String::from("apple"), 1);
+    basket.insert(String::from("mango"), 2);
 
     basket
 }

exercises/collections/hashmap2.rs

@@ -12,8 +12,6 @@
 // Execute the command `rustlings hint hashmap2` if you need
 // hints.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 #[derive(Hash, PartialEq, Eq)]
@@ -38,6 +36,9 @@ 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!
+        if basket.get(&fruit) == None {
+            basket.insert(fruit, 1);
+        }
     }
 }
 

exercises/collections/vec1.rs

@@ -4,11 +4,9 @@
 // Make me compile and pass the test!
 // Execute the command `rustlings hint vec1` if you need hints.
 
-// 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)
 }

exercises/collections/vec2.rs

@@ -7,12 +7,11 @@
 // Execute the command `rustlings hint vec2` if you need
 // hints.
 
-// 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].