239. 滑动窗口最大值

https://leetcode-cn.com/problems/sliding-window-maximum/

给定一个数组 nums，有一个大小为 k 的滑动窗口从数组的最左侧移动到数组的最右侧。你只可以看到在滑动窗口内的 k 个数字。滑动窗口每次只向右移动一位。

返回滑动窗口中的最大值。

进阶:

你能在线性时间复杂度内解决此题吗？

示例:

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

  滑动窗口的位置                最大值
---------------               -----
[1  3  -1] -3  5  3  6  7       3
 1 [3  -1  -3] 5  3  6  7       3
 1  3 [-1  -3  5] 3  6  7       5
 1  3  -1 [-3  5  3] 6  7       5
 1  3  -1  -3 [5  3  6] 7       6
 1  3  -1  -3  5 [3  6  7]      7

提示:

1 <= nums.length <= 10^5
-10^4 <= nums[i] <= 10^4
1 <= k <= nums.length

from collections import deque

class Solution(object):
    def maxSlidingWindow(self, nums, k):
        """
        :type nums: List[int]
        :type k: int
        :rtype: List[int]
        """
        window = deque()
        res = []

        for i in range(len(nums)):
            if i < k - 1:
                self.push(window, nums[i])
            else:
                self.push(window, nums[i])
                res.append(window[0])
                self.remove(window, nums[i-k+1])
        return res

    def push(self, window, n):
        while window and window[-1] < n:
            window.pop()
        window.append(n)

    def remove(self, window, n):
        if window and window[0] == n:
            window.popleft()