_126sliding.java

import java.util.*;
public class _126sliding {
    static class Pair implements Comparable<Pair>{
        int val;
        int idx;
        public Pair(int val,int idx){
            this.val=val;
            this.idx=idx;
        }
        @Override
        public int compareTo(Pair p2){
            return p2.val-this.val;
        }
    }

    public static void main(String[] args) {
        int arr[]={1,3,-1,-3,5,3,6,7};
        int k=3;
        int res[]=new int[arr.length-k+1];
        PriorityQueue<Pair> pq = new PriorityQueue<>();

        for(int i=0;i<k;i++){
            pq.add(new Pair(arr[i],i));
        }
        res[0]=pq.peek().val;
        for(int i =k; i<arr.length;i++){
            while(pq.size()>0 && pq.peek().idx<= (i-k)){
                pq.remove();
            }
            pq.add(new Pair(arr[i],i));
            res[i-k+1] = pq.peek().val;
        }
        for(int i = 0; i<res.length;i++){
            System.out.print(res[i]+ " ");
        }
    }
}