题目描述

blablabla

样例

blablabla

prim

问题：

怎样才能用BufferedReader来读这种输入有两个空格有一个空格的数据?

Java 代码

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

public class Main{
    private static int N = 110;
    private static int n,INF = 0x3f3f3f3f;
    private static int[][] g = new int[N][N];

    private static int[] dist = new int[N];
    private static boolean[] st = new boolean[N];

    private static int prim(){
        Arrays.fill(dist,INF);
        int ans = 0;
        for(int i = 0 ; i < n ;i++){
            int t = -1;
            for(int j = 1 ; j <= n ; j++){
                while(!st[j] && (t == -1 || dist[t] > dist[j])){
                    t = j;
                }
            }
            if(i != 0 && dist[t] == INF) return INF;
            if(i != 0) ans += dist[t];
            st[t] = true;
            for(int j = 1 ; j <= n ; j++){
                dist[j] = Math.min(dist[j],g[t][j]);
            }
        }
        return ans;
    }
    public static void main(String[] args) throws IOException{
        //BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        for(int i = 1 ; i <= n ; i++){
            //String[] s = in.readLine().split(" ");
            for(int j = 1 ; j <= n ; j++){
                g[i][j] = sc.nextInt();
            }
        }
        int ans = prim();
        if(ans == INF) System.out.println("impossible");
        else System.out.println(ans);
    }
}