Kortit II

input/code.cpp: In function 'void solve()':
input/code.cpp:33:11: warning: suggest parentheses around comparison in operand of '^' [-Wparentheses]
   33 |     if (a == 0 ^ b == 0) {
      |         ~~^~~~

#include <bits/stdc++.h>
using namespace std;
#define MOD 1000000007

vector<vector<long long>> computeBinomialCoefficients(long long n) {
    vector<vector<long long>> C(n + 1, vector<long long>(n + 1, 0));
    
    for (long long i = 0; i <= n; i++) {
        C[i][0] = C[i][i] = 1; // Base cases
        for (long long j = 1; j < i; j++) {
            C[i][j] = (C[i-1][j-1] + C[i-1][j]) % MOD;
        }
    }
    return C;
}

vector<long long> computeFactorials(long long n) {
    vector<long long> F(n+1, 1);
    for (long long i = 1; i <= n; i++) {
        F[i] = (i*F[i-1]) % MOD;
    }
    return F;
}

vector<vector<long long>> C = computeBinomialCoefficients(2000);
vector<long long> F = computeFactorials(2000);

void solve() {
    long long n, a, b;
    cin >> n >> a >> b;

    // edge cases
    if (a == 0 ^ b == 0) {
        cout << 0 << endl;
        return;
    }
    if (a + b > n) {
        cout << 0 << endl;
        return;
    }
    if (a == 0 && b == 0) {
        cout << F[n] << endl;
        return;
    }

    long long m = a+b;
    a = min(a, b);

    long long coeff = ((C[n][m]*C[n][m] % MOD)*F[m] % MOD) * F[n-m] % MOD;
    //<dumb way>
    vector<long long> target_perm;
    vector<long long> permutation;
    long long solutions = 0;

    for (int i = 0; i < m; i++) {
        target_perm.push_back(i);
        permutation.push_back(i);
    }

    do {

        b = a;

        for (int i = 0; i < m; i++) {
            if(target_perm[i]==permutation[i]){
                b = 1; 
                break;}
            if(target_perm[i]<permutation[i]) b--;
        }
        if (b==0)
            solutions++;
    } while (next_permutation(permutation.begin(),permutation.end()));
    if (solutions == 0) solutions++;
    // </dumb way>
    cout << (solutions * coeff % MOD)<< endl;
    return;
}

int main() {
    int n;
	cin >> n;
    for (int i = 0; i < n; i++)
    {
        solve();
    }
}

Test 1

Group: 1, 2, 3, 4, 5

Verdict: ACCEPTED

Test 2

Group: 2, 3, 4, 5

Verdict: ACCEPTED

Test 3

Group: 3, 4, 5

Verdict: TIME LIMIT EXCEEDED

Test 4

Group: 4, 5

Verdict: TIME LIMIT EXCEEDED

Test 5

Group: 5

Verdict: TIME LIMIT EXCEEDED

Test 6

Group: 5

Verdict: TIME LIMIT EXCEEDED