Vectors

Vectors

Vec<T> is Rust's growable array. It stores elements contiguously on the heap.

Creating Vectors

let empty: Vec<i32> = Vec::new();
let v = vec![1, 2, 3, 4, 5];   // macro shorthand
let zeros = vec![0; 10];         // ten zeros

Modifying Vectors

let mut v = Vec::new();
v.push(1);
v.push(2);
v.pop();     // removes last — returns Option<T>
v.insert(0, 99); // insert at index
v.remove(0);     // remove at index
v.sort();        // sort in place
v.dedup();       // remove consecutive duplicates (sort first)
v.retain(|&x| x > 0); // keep elements matching predicate
v.extend([4, 5, 6]);   // append elements

Accessing Elements

v[0]         // panics if out of bounds
v.get(0)     // returns Option<&T> — safe
v.first()    // Option<&T>
v.last()     // Option<&T>

Iteration

for x in &v { println!("{}", x); }
for x in &mut v { *x *= 2; }
for x in v { /* consumes v */ }

Partition and Drain

let (evens, odds): (Vec<i32>, Vec<i32>) = v.into_iter().partition(|&x| x % 2 == 0);

Your Task

1. remove_duplicates(v: Vec<i32>) -> Vec<i32> — returns sorted vec with duplicates removed.
2. flatten(vecs: Vec<Vec<i32>>) -> Vec<i32> — flattens a vec of vecs.
3. two_pass_max(v: &[i32]) -> Option<i32> — returns the maximum element.
4. partition_evens_odds(v: Vec<i32>) -> (Vec<i32>, Vec<i32>) — splits into (evens, odds).