[백준] 11724번 : 연결 요소의 개수 - Java(자바)

https://www.acmicpc.net/problem/11724

import java.util.*;

public class Main {
    static int arr[][];
    static boolean check[];
    static int n;

    static void dfs(int a){
        check[a]=true;
    
        for(int i=1;i<=n;i++){
            if(arr[a][i]==1 && check[i]==false) dfs(i);
        }
    }
    
    public static void main(String args[]) {
        Scanner s=new Scanner(System.in);
        n=s.nextInt();
        int m=s.nextInt();
        arr=new int[n+1][n+1];
        check=new boolean[n+1];
        while(m-->0){
            int u=s.nextInt();
            int v=s.nextInt();
            arr[u][v]=arr[v][u]=1;
        }
        int count=0;
        for(int i=1;i<=n;i++){
            if(check[i]==false){
                dfs(i);
                count++;
            }
        }
        System.out.print(count);
    }
}