Lennot

import java.util.ArrayList;
import java.util.List;

public class Lents2 {
	static int cityCount, flightCount;
	
	static int[][] flights;
	static long[] costs;
	
	static long lowestCost;
	
	public static long getLowestCost(int from, int to) {
		long result = Long.MAX_VALUE;
		
		for(int i = 0; i < flightCount; i++)
			if(flights[i][0] == from && flights[i][1] == to && costs[i] < result)
				result = costs[i];
		
		if(result == Long.MAX_VALUE) Integer.parseInt("no");
		return result;
	}
	
	public static boolean flightExists(int from, int to) {
		for(int i = 0; i < flightCount; i++)
			if(flights[i][0] == from && flights[i][1] == to)
				return true;
		
		return false;
	}
	
	public static List<Integer> getAppended(List<Integer> list, int value) {
		List<Integer> newList = new ArrayList<Integer>();
		
		newList.addAll(list);
		newList.add(value);
		return newList;
	}
	
	public static void fly(int from, long curCost, int flightNum, List<Integer> alreadyBeenOdd, List<Integer> alreadyBeenEven) {
		long addedPrice;
		
		if(from == cityCount - 1) {
			if(curCost < lowestCost) lowestCost = curCost;
			return;
		}
		
		for(int i = 0; i < flightCount; i++) {
			if(flights[i][0] == from && flightExists(from, flights[i][1])) {
				addedPrice = flightNum % 2 == 0 ? 0 : getLowestCost(from, flights[i][1]);
				
				if(curCost + addedPrice < lowestCost
						&& ((flightNum % 2 == 0 && !alreadyBeenEven.contains(flights[i][1]))
						|| (flightNum % 2 != 0 && !alreadyBeenOdd.contains(flights[i][1])))) {
					
					fly(flights[i][1], curCost + addedPrice, flightNum+1,
							flightNum % 2 == 0? alreadyBeenOdd : getAppended(alreadyBeenOdd, flights[i][1]),
							flightNum % 2 == 0? getAppended(alreadyBeenEven, flights[i][1]) : alreadyBeenEven);
				}
			}
		}
	}
	
	public static void main(String[] args) {
		IO oi = new IO();
		
		cityCount = oi.nextInt();
		flightCount = oi.nextInt();
		
		flights = new int[flightCount][2];
		costs = new long[flightCount];
		
		for(int i = 0; i < flightCount; i++) {
			flights[i] = new int[] { oi.nextInt()-1, oi.nextInt()-1 };
			costs[i] = oi.nextLong();
		}
		
		lowestCost = 0;
		for(int i = 0; i < flightCount; i++) lowestCost += costs[i];
		
		fly(0, 0, 1, new ArrayList<Integer>(), new ArrayList<Integer>());
		
		oi.println(lowestCost);
		oi.close();
	}
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 7

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 8

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 11

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 12

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 13

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 14

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 15

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 16

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 17

Group: 3

Verdict: TIME LIMIT EXCEEDED