feat: modified queue to use VecDeque instead of Vec (#98)

Also removed pointless return value of Queue::enqueue (if it fails it panics)

src/data_structures/queue.rs

@@ -1,15 +1,18 @@
+use std::collections::VecDeque;
+
 pub struct Queue<T> {
- vec: Vec<T>,
+ vec: VecDeque<T>,
 }
 
 impl<T> Queue<T> {
  pub fn new() -> Self {
- Queue { vec: Vec::new() }
+ Queue {
+ vec: VecDeque::new(),
+ }
  }
 
- pub fn enqueue(&mut self, item: T) -> bool {
- self.vec.push(item);
- true
+ pub fn enqueue(&mut self, item: T) {
+ self.vec.push_back(item);
  }
 
  pub fn len(&self) -> usize {
@@ -21,15 +24,11 @@ impl<T> Queue<T> {
  }
 
  pub fn peek(&self) -> Option<&T> {
- self.vec.first()
+ self.vec.front()
  }
 
  pub fn dequeue(&mut self) -> Option<T> {
- if self.is_empty() {
- None
- } else {
- Some(self.vec.remove(0))
- }
+ self.vec.pop_front()
  }
 }