剑指 Offer 59 - I. 滑动窗口的最大值

https://leetcode-cn.com/problems/hua-dong-chuang-kou-de-zui-da-zhi-lcof/
给定一个数组 nums 和滑动窗口的大小 k，请找出所有滑动窗口里的最大值。

示例:
输入: nums = [1,3,-1,-3,5,3,6,7], 和 k = 3
输出: [3,3,5,5,6,7]

class Solution {
    public int[] maxSlidingWindow(int[] nums, int k) {
        if(nums.length == 0 || nums == null) return new int[0];
        Deque deque = new LinkedList<>();
        int[] res = new int[nums.length - k + 1];
        int t = 0;
        for(int i = 0; i < nums.length; i++){
           if(!deque.isEmpty() && i - deque.peekFirst() >= k){
               deque.pollFirst();
           }
            while(!deque.isEmpty() && nums[deque.peekLast()] < nums[i]){
                deque.pollLast();
            } 
            deque.offer(i);
            // if(i>=2) //
            if(i >= k-1) res[t++] = nums[deque.peek()];
        }
        return res;
    }
}

//也可以加对应元素，判断对应位置的元素和deque对应是否相等