[Algorithm] 백준 알고리즘 11724 (연결 요소의 개수)

 

java 코드

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.LinkedList;
import java.util.Queue;
import java.util.StringTokenizer;

public class LinkCount {
	static int N, M, count;
	static int map[][];
	static boolean visited[];
	
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		N=Integer.parseInt(st.nextToken());
		M=Integer.parseInt(st.nextToken());
		map = new int[N][N];
		visited = new boolean[N];
		while(M!=0) {
			st = new StringTokenizer(br.readLine());
			int x=Integer.parseInt(st.nextToken());
			int y=Integer.parseInt(st.nextToken());
			map[x-1][y-1]=map[y-1][x-1]=1;
			M--;
		}
		for(int i=0; i<N; i++) {
			if(!visited[i]) {
				solve(i);
				count++;
			}
		}
		System.out.println(count);
	}
	static void solve(int i) {
		Queue<Integer> q = new LinkedList<>();
		q.add(i);
		visited[i]=true;
		
		while(!q.isEmpty()) {
			int x = q.poll();
		for(int a=0; a<N; a++) {
			if(map[x][a]==1&&!visited[a]) {
				visited[a]=true;
				q.add(a);
			}
		}
		}
	}
}