[java] 백준 11724: 연결 요소의 개수

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

11724번: 연결 요소의 개수

 

 

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

public class Main {

	static boolean flag = false;
	static boolean visited[];
	static ArrayList<Integer>[] arr;
	
	public static void DFS(int i) {
		
		if(visited[i]) return;
		visited[i] = true;
		for(int x: arr[i]) {
			if(!visited[x]) {
				DFS(x);
			}
		}
		
	
	}
	
	public static void main(String[] args) throws IOException {
	
		Scanner kb = new Scanner(System.in);
		int n=kb.nextInt();
		int m=kb.nextInt();
		
		arr=new ArrayList[n+1];
		visited = new boolean[n+1];
		
		
		for(int i=1; i<=n; i++){
			arr[i] =new ArrayList<Integer>();
		}
		
		for(int i=0; i<m; i++){
			int a=kb.nextInt();
			int b=kb.nextInt();
			arr[a].add(b);
			arr[b].add(a);
		}
		
		int cnt =0;
		for(int i=1; i<=n; i++) {
			if(!visited[i]) {
				cnt++;
				DFS(i);
			}
			
		}
		System.out.println(cnt);	
		
	}


}