Lennot

/*
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/**
 *
 * @author alexey
 */import java.util.*;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;
public class Datis {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        IO io =new IO();
        
        int city=io.nextInt();
        int connect=io.nextInt();
        int[][] cities = new int[city+1][2];
        int i=1;
       
      
      ArrayList<ArrayList<int[]>> connections= new  ArrayList<ArrayList<int[]>>();
      connections.add(new ArrayList());
      Comparator<int[]> comparator = new comp();
      PriorityQueue<int[]> queue = 
            new PriorityQueue<int[]>(connect, comparator);
        for (int j = 0; j < city; j++) {
            connections.add(new ArrayList<int[]>());
        }
        
        for (int j = 0; j < connect; j++) {
            int a=io.nextInt();
            int b=io.nextInt();
            int c=io.nextInt();
            int[] d =new int[3];
            d[0]=b;
            d[1]=c;
            d[2]=a;
            connections.get(a).add(d);
        }
        
        for(int[] x :connections.get(1)){
                    
                    queue.add(x);
                }
        while(!queue.isEmpty()){
            int[] a= queue.poll();
            if(cities[a[0]][0]==0){
                cities[a[0]][0]+=a[1];
                cities[a[0]][1]=1-cities[a[2]][1];
                for(int[] x :connections.get(a[0])){
                    x[1]=cities[a[0]][0]+cities[a[2]][1]*x[1];
                    queue.add(x);
                }
            }
        }
        
        io.print(cities[city][0]);
        io.close();
     
    }
    
    public static class comp implements Comparator<int[]>{

        @Override
        public int compare(int[] t, int[] t1) {
            if(t[1]>t1[1]){
                return 1;
            } 
            if(t[1]<t1[1]){
                return -1;
            }  
            return 0;
        }
        
        
    }
    
    
     static class IO extends PrintWriter {
	private BufferedReader r;
	private StringTokenizer s;
	
	public IO() {
		super(new BufferedOutputStream(System.out));
		r = new BufferedReader(new InputStreamReader(System.in));
	}
	
	public String nextLine() {
		String s = null;
		try {
			s = r.readLine();
		} catch (Exception e) {}
		if(s == null) throw new NoSuchElementException();
		return s;
	}
	
	public String next() {
		while (s == null || !s.hasMoreElements()) {
			s = new StringTokenizer(nextLine());
		}
		return s.nextToken();
	}
        public int nextInt() {
		return Integer.parseInt(next());
	}
}
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: WRONG ANSWER

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

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: WRONG ANSWER

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: ACCEPTED

Test 16

Group: 3

Verdict: ACCEPTED

Test 17

Group: 3

Verdict: WRONG ANSWER