Merkkijonot

#include <iostream>
#include <string>
#include <math.h>
#include <map>
#include <algorithm>
#include <vector>
#include <fstream>
#include <set>
#include <unordered_map>
#include <queue>
#include <chrono>
#include <climits>
#include <stack>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace std::chrono;
using namespace __gnu_pbds;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;
#define S second
#define F first
//#define A 999999999999999999LL
#define M 1000000007
#define N 202020
#define REDIR                 \
	ifstream in("input.txt"); \
	cin.rdbuf(in.rdbuf());

int n;

ll d[505][300][300];
int main() {
	//REDIR;
	cin >> n;
	d[0][0][0] = 1;
	int totalA = 0;
	int totalB = 0;
	for (int i = 0; i < n; i++)
	{
		string s; cin >> s;
		int myA = count(s.begin(), s.end(), 'a');
		int myB = count(s.begin(), s.end(), 'b');
		totalA += myA;
		totalB += myB;
		if (i == 0) {
			d[i][myA][myB] = 1;
			continue;
		}
		for (int a = 0; a < 251; a++)
		{
			for (int b = 0; b < 251; b++)
			{
				d[i][a][b] += d[i-1][a][b];
				d[i][a][b] %= M;
				d[i][a + myA][b+myB] += d[i-1][a][b];	
				d[i][a+myA][b+myB] %= M;
			}
		}
		
	}
	if (totalA % 2 == 1 || totalB % 2 == 1) {
		cout << 0; return 0;
	}
	cout << d[n-1][totalA/2][totalB/2];
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 2, 3

Verdict: ACCEPTED

Test 6

Group: 2, 3

Verdict: ACCEPTED

Test 7

Group: 2, 3

Verdict: ACCEPTED

Test 8

Group: 2, 3

Verdict: ACCEPTED

Test 9

Group: 3

Verdict: ACCEPTED

Test 10

Group: 3

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 2, 3

Verdict: ACCEPTED

Test 16

Group: 3

Verdict: ACCEPTED