Peli

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;

public class Main {
    private static class Query {
        int from;
        int to;
        int moves;

        Query(int from, int to, int moves) {
            this.from = from;
            this.to = to;
            this.moves = moves;
        }

        @Override
        public int hashCode() {
            return Arrays.hashCode(new int[]{from, to, moves});
        }
    }

    private static ArrayList<ArrayList<Integer>> paths = new ArrayList<>();
    private static HashMap<Query, Boolean> queryMemory = new HashMap<>();

    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String[] inputLine1 = reader.readLine().trim().split(" ");
        int n = Integer.parseInt(inputLine1[0]);
        int m = Integer.parseInt(inputLine1[1]);
        int q = Integer.parseInt(inputLine1[2]);

        for (int planet = 0; planet < n; planet++) {
            paths.add(new ArrayList<>());
        }

        for (int pathIndex = 0; pathIndex < m; pathIndex++) {
            String[] inputLine2 = reader.readLine().trim().split(" ");
            int a = Integer.parseInt(inputLine2[0]) - 1;
            int b = Integer.parseInt(inputLine2[1]) - 1;

            paths.get(a).add(b);
            paths.get(b).add(a);
        }

        for (int i = 0; i < q; i++) {
            String[] inputLine3 = reader.readLine().trim().split(" ");
            int from = Integer.parseInt(inputLine3[0]) - 1;
            int to = Integer.parseInt(inputLine3[1]) - 1;
            int moves = Integer.parseInt(inputLine3[2]);
            System.out.println(query(new Query(from, to, moves)) ? "YES" : "NO");
        }
    }

    private static boolean query(Query query) {
        if (queryMemory.containsKey(query)) return queryMemory.get(query);

        boolean result = false;

        if (query.moves == 0) {
            result = query.from == query.to;
        } else {
            int originalFrom = query.from;
            query.moves--;

            for (int destination : paths.get(query.from)) {
                query.from = destination;
                if (query(query)) {
                    result = true;
                }
            }

            query.moves++;
            query.from = originalFrom;
        }
        

        queryMemory.put(query, result);
        return result;
    }
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: ACCEPTED

Test 3

Group: 2

Verdict: RUNTIME ERROR

Exception in thread "main" java.lang.StackOverflowError
	at Main.query(Main.java:71)
	at M...

Test 4

Group: 1, 2

Verdict: ACCEPTED

Test 5

Group: 1, 2

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: RUNTIME ERROR

Exception in thread "main" java.lang.StackOverflowError
	at Main.query(Main.java:71)
	at M...

Test 7

Group: 2

Verdict: RUNTIME ERROR

Exception in thread "main" java.lang.StackOverflowError
	at Main.query(Main.java:71)
	at M...

Test 8

Group: 1, 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 2

Verdict: RUNTIME ERROR

Exception in thread "main" java.lang.StackOverflowError
	at Main.query(Main.java:71)
	at M...