[백준 2606] 바이러스 (S3)

📍 문제 

https://www.acmicpc.net/problem/2606

 

📍 전체 코드

 

인접행렬을 통한 풀이

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.StringTokenizer;

public class boj_2606 {
    static int n, m;
    static int[][] computers;
    static boolean[] visited;
    static int result = 0;

    public static void main(String[] args) throws IOException {
       BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
       n = Integer.parseInt(br.readLine());
       m = Integer.parseInt(br.readLine());

       computers = new int[n + 1][n + 1];
       visited = new boolean[n + 1];

       for (int i = 0; i < m; i++) {
          StringTokenizer st = new StringTokenizer(br.readLine());
          int a = Integer.parseInt(st.nextToken());
          int b = Integer.parseInt(st.nextToken());
          computers[a][b] = computers[b][a] = 1;
       }
       dfs(1);
       System.out.println(result);
    }

    public static void dfs(int node) {
       visited[node] = true;

       for (int i = 1; i < computers[node].length; i++) {
          // 방문하지 않았고, 연결되어있다면
          if(!visited[i] && computers[node][i] == 1) {
             result++;
             dfs(i);
          }
       }
    }
}