Tunnels

import java.util.ArrayList;
import java.util.Scanner;
import java.util.StringTokenizer;

/**
 * Created by Florian on 22-Jan-17.
 */
public class Tunnels {
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		StringTokenizer st = new StringTokenizer(sc.nextLine());
		int n = Integer.parseInt(st.nextToken());
		int m = Integer.parseInt(st.nextToken());
		int[] inoutDif = new int[n];//-in+out
		ArrayList<ArrayList<Integer>> connections = new ArrayList<>();
		for (int i = 0; i < n; i++) {
			connections.add(new ArrayList<>());
		}
		for (int i = 0; i < m; i++) {
			st = new StringTokenizer(sc.nextLine());
			int a = Integer.parseInt(st.nextToken()) - 1;
			int b = Integer.parseInt(st.nextToken()) - 1;
			inoutDif[a]++;
			inoutDif[b]--;
			connections.get(a).add(b);
			connections.get(b).add(a);
		}
		//is connected?
		boolean[] visited = new boolean[n];
		int count = 0;
		for (int i = 0; i < n; i++) {
			if (!visited[i]) {
				int daysUsed = DFS(visited, connections, i, inoutDif);
				daysUsed = Math.max(1, daysUsed);
				count += daysUsed;
			}
		}
		System.out.println(count);

	}

	private static int DFS(boolean[] visited, ArrayList<ArrayList<Integer>> connections, int i, int[] inoutDif) {
		visited[i] = true;
		int daysCount = Math.max(0, inoutDif[i]);
		for (Integer room : connections.get(i)) {
			if (!visited[room])
				daysCount += DFS(visited, connections, room, inoutDif);
		}
		return daysCount;
	}
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: WRONG ANSWER

Test 3

Group: 1

Verdict: WRONG ANSWER

Test 4

Group: 1

Verdict: WRONG ANSWER

Test 5

Group: 1

Verdict: WRONG ANSWER

Test 6

Group: 2

Verdict: WRONG ANSWER

Test 7

Group: 2

Verdict: WRONG ANSWER

Test 8

Group: 2

Verdict: WRONG ANSWER

Test 9

Group: 2

Verdict: WRONG ANSWER

Test 10

Group: 2

Verdict: WRONG ANSWER

Test 11

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 12

Group: 3

Verdict: WRONG ANSWER

Test 13

Group: 3

Verdict: WRONG ANSWER

Test 14

Group: 3

Verdict: WRONG ANSWER

Test 15

Group: 3

Verdict: WRONG ANSWER