Submission #1758413

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Source Code Expand

import java.util.Scanner;

public class Main {

	static int n, m;
	static boolean graph[][];
	static boolean vis[];

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		n = sc.nextInt();
		m = sc.nextInt();
		graph = new boolean[n][n];
		vis = new boolean[n];
		for(int i = 0 ; i < m ; i++) {
			int a = sc.nextInt() - 1;
			int b = sc.nextInt() - 1;
			graph[a][b] = graph[b][a] = true;
		}
		for(int i = 0 ; i < n ; i++) vis[i] = false;
		vis[0] = true;
		System.out.println(dfs(0));
	}

	public static int dfs(int x) {
		boolean all_vis = true;
		for(int i = 0 ; i < n ; i++) {
			if(vis[i] == false) all_vis = false;
		}
		if(all_vis == true) return 1;
		int ret = 0;
		for(int i = 0 ; i < n ; i++) {
			if(vis[i] == true) continue;
			if(graph[x][i] == false) continue;
			vis[i] = true;
			ret += dfs(i);
			vis[i] = false;
		}
		return ret;
	}

}

Submission Info

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