[java] 백준 13023: ABCDE

https://www.acmicpc.net/problem/13023

13023번: ABCDE

 

그래프 기초

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,int d) {
		if(d==5) {
			flag=true;
			return;
		}
		visited[i] = true;
		for(int x: arr[i]) {
			if(!visited[x]) {
				DFS(x,d+1);
			}
		}
		visited[i]=false;
		
	
	}
	
	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];
		visited = new boolean[n];
		
		
		for(int i=0; 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);
		}
		
		for(int i=0; i<n; i++) {
			DFS(i,1);
			if(flag) break;
		}
		
	
		if(flag) System.out.println(1);
		else System.out.println(0);	
		
	}


}