题解 | #滑动窗口的最大值#

import java.util.*;

//利用堆的方法解决，大根堆堆顶是滑动窗口的最大值

public class Solution {

public ArrayList<Integer> maxInWindows(int [] num, int size) {
    if(size > num.length || size == 0){
        return new ArrayList();
    }

     //引入Compactor形成大根堆

    PriorityQueue<Integer> heap = new PriorityQueue<Integer>(new Comparator<Integer>() {
        @Override
        public int compare(Integer o1, Integer o2) {
            return o2 - o1;
        }
    });
    
    ArrayList<Integer> resList = new ArrayList<Integer>();
    int left = 0;
    int right = size;
    for(int i = 0; i < size; i++){
        heap.add(num[i]);
    }

    while(right < num.length){
        
        resList.add(heap.peek());
        heap.remove(num[left++]);
        heap.add(num[right++]);
    }
    
    resList.add(heap.peek());
    return resList;
}

}