滑动窗口模板题（对读写性能要求贼高）

Posted 2020-12-07 doubest

7、滑动窗口模板题

题目链接：

https://www.acwing.com/problem/content/156/

题解：

做滑动窗口，一般先假想成普通队列来做，再分析题目的单调性，改进优化

AC代码：

import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
        // 对输入数据进行初始化
        String[] s1 = reader.readLine().split(" ");
        int n = Integer.parseInt(s1[0]);
        int k = Integer.parseInt(s1[1]);
        int[] a = new int[n], q = new int[n];
        String[] s = reader.readLine().split(" ");
        for (int i = 0; i < n; i++)
            a[i] = Integer.parseInt(s[i]);
        
        int hh = 0, ee = -1;
        for(int i = 0;i < n;i ++) {
            while(hh <= ee && q[hh] < i - k + 1) hh++;
            while(hh <= ee && a[q[ee]] >= a[i] ) ee--;
            q[++ee] = i;
            if(i >= k - 1) log.write(a[q[hh]] + " ");
        }
        log.write("
");
        hh = 0; ee = -1;
        for(int i = 0;i < n;i ++) {
            while(hh <= ee && q[hh] < i - k + 1) hh++;
            while(hh <= ee && a[q[ee]] <= a[i] ) ee--;
            q[++ee] = i;
            if(i >= k - 1) log.write(a[q[hh]] + " ");
        }
        
        // 关闭输入输出流
        log.flush(); // 如果不flush，没有标准输出
        reader.close();
        log.close();
    }
}