Java遇到输入速度瓶颈时的解决办法

Posted 2021-02-20 Doubest

数据输入

一般常用的数据输入方法有两种：Scanner和BufferedReader。BufferedReader可以读一行，速度比Scanner快，所以数据较多的时候使用。注意BufferedReader用完记得关。

Scanner

import java.util.*;

public class Main{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt(); // String: next(), double: nextDouble()
        int[] nums = new int[n];
        for (int i = 0; i < n; i++)
            nums[i] = scan.nextInt();
        // ...
    }
}

BufferedReader

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));
        int n = Integer.parseInt(reader.readLine());
        int[] nums = new int[n];
        String[] strs = reader.readLine().split(" ");
        for (int i = 0; i < n; i++)
            nums[i] = Integer.parseInt(strs[i]);
        // ...
        reader.close(); // 记得关闭
    }
}