import java.util.ArrayDeque;
import java.util.Deque;
/*
* @lc app=leetcode.cn id=239 lang=java
*
* [239] 滑动窗口最大值
*/
// @lc code=start
class Solution {
public int[] maxSlidingWindow(int[] nums, int k) {
if (nums == null || k == 0) return new int[0];
int n = nums.length;
int[] res = new int[n - k + 1];
int idx = 0;
Deque<Integer> q = new ArrayDeque<>();
for (int i = 0; i < n; i++) {
while (!q.isEmpty() && q.peekFirst() < i - k + 1)
q.pollFirst();
while (!q.isEmpty() && nums[i] >= nums[q.peekLast()])
q.pollLast();
q.addLast(i);
if (i >= k - 1) {
res[idx++] = nums[q.peekFirst()];
}
}
return res;
}
}
// @lc code=end