use std::collections::VecDeque;

impl Solution {
    pub fn max_sliding_window(nums: Vec<i32>, k: i32) -> Vec<i32> {
        let mut output = vec![];
        let mut q: VecDeque<usize> = VecDeque::new();
    
        let (mut l, mut r) = (0, 0);
    
        while r < nums.len() {
            while !q.is_empty() && nums[r] > nums[*q.back().unwrap()] {
                q.pop_back();
            }
    
            q.push_back(r);
    
            if l > *q.front().unwrap() {
                q.pop_front();
            }
    
            if r + 1 >= k as usize {
                output.push(nums[*q.front().unwrap()]);
                l += 1;
            }
            
            r += 1;
        }
    
        output
    }
}