力扣labuladong一刷day51天單調(diào)棧應(yīng)用

一、239. 滑動(dòng)窗口最大值

題目鏈接：https://leetcode.cn/problems/sliding-window-maximum/
思路：滑動(dòng)窗口最大值，既要維護(hù)加入的時(shí)間順序，又要

class Solution {public int[] maxSlidingWindow(int[] nums, int k) {int[] res = new int[nums.length - k + 1];Queue queue = new Queue();for (int i = 0; i < k; i++) {queue.push(nums[i]);}int j = 0;res[j++] = queue.getMax();for (int i = k; i < nums.length; i++) {queue.pop(nums[i-k]);queue.push(nums[i]);res[j++] = queue.getMax();}return res;}class Queue {LinkedList<Integer> stack = new LinkedList<>();void push(int n) {while (!stack.isEmpty() && n > stack.getLast()) {stack.pollLast();}stack.addLast(n);}void pop(int n) {if (n == stack.getFirst()) {stack.pollFirst();}}int getMax() {return stack.getFirst();}}
}