백준 1325 효율적인 해킹(Java)

https://www.acmicpc.net/problem/1325

1325번: 효율적인 해킹

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Java 코드

 

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import java.util.Scanner;
import java.util.ArrayList;

public class Main {

  static int n;
  static int m;
  static int[] arr;
  static boolean[] visit;
  static ArrayList<ArrayList<Integer>> list = new ArrayList<>();

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    StringBuilder sb = new StringBuilder();

    int max = -1;
    n = sc.nextInt();
    m = sc.nextInt();
    arr = new int[n + 1];
    for(int i = 0; i <= n; i++) list.add(new ArrayList<>());
    
    for(int i = 0; i < m; i++) {
      int a = sc.nextInt();
      int b = sc.nextInt();
      list.get(a).add(b);
    }

    for(int i = 1; i <= n; i++) {
      visit = new boolean[n + 1];
      dfs(i);
    }

    for(int i = 1; i <= n; i++) max = Math.max(max, arr[i]);

    for(int i = 1; i <= n; i++) {
      if(arr[i] == max) sb.append(i+" ");
    }

    System.out.println(sb);
  }

  public static void dfs(int num) {
    visit[num] = true;
    for(int i : list.get(num)) {
      if(visit[i] == false) {
        arr[i]++;
        dfs(i);
      }
    }
  }
  
}