Lähetit

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

public class Main {

    public static void main(String[] args) {
        long M = 1000000007L;
        int TAULUN_KOKO = 200;

        Scanner lukija = new Scanner(System.in);
        long vaihtoehtoja = 0;

        int koko = lukija.nextInt();
        int lahetteja = lukija.nextInt();

        long[][] taulu = new long[TAULUN_KOKO][TAULUN_KOKO];
        taulu[0][0] = 1;
        
        ArrayList<Integer> lapikaytavat = new ArrayList<>();
        for (int i = 1; i < koko; i++) {
            lapikaytavat.add(i);
            lapikaytavat.add(i);
        }
        lapikaytavat.add(koko);

        for (int i = 0; i < lapikaytavat.size(); i++) {
            int nykyinen = lapikaytavat.get(i);

            for (int j = i; j >= 0; j--) {
                for (int k = 0; k < j + 1; k++) {
                    if (taulu[j][k] != 0) {
                        if ((nykyinen & 1) != 0) {
                            taulu[j + 1][k + 1] += taulu[j][k] * (nykyinen - k);
                        } else {
                            taulu[j + 1][k] += taulu[j][k] * (nykyinen - (j - k));
                        }
                    }
                }
            }
        }

        for (int i = 0; i <= koko; i++) {
            vaihtoehtoja += taulu[lahetteja][i];
            vaihtoehtoja = vaihtoehtoja % M;
        }
        System.out.println(vaihtoehtoja);
    }
}

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: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

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: RUNTIME ERROR

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 200
	at Main.main(Main.java:44)