Merkkijonot

input/code.cpp: In function 'int main()':
input/code.cpp:39:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |     for (int i = 0; i < counts.size() - 1; i++) {
      |                     ~~^~~~~~~~~~~~~~~~~~~
input/code.cpp:47:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |             for (int j = cur.fi + 1; j < counts.size(); j++) {
      |                                      ~~^~~~~~~~~~~~~~~

#include <bits/stdc++.h>
#define pb push_back
#define ii pair<int,int>
#define fi first
#define se second
#define ll long long
using namespace std;

int N, tac, tbc;
vector<ii> counts;

int main() {
    ios_base::sync_with_stdio(false);

    cin >> N;

    tac = 0, tbc = 0;

    while (N--) {
        string s; cin >> s;
        int ac = 0, bc = 0;

        for (auto c : s) {
            if (c == 'a') ac++;
            else bc++;
        }

        tac += ac;
        tbc += bc;

        counts.pb(ii(ac, bc));
    }

    tac /= 2;
    tbc /= 2;

    ll ans = 0;

    for (int i = 0; i < counts.size() - 1; i++) {
        queue<pair<int, ii>> q;
        q.push(make_pair(i, counts[i]));

        while(!q.empty()) {
            auto cur = q.front();
            q.pop();

            for (int j = cur.fi + 1; j < counts.size(); j++) {
                if (cur.se.fi + counts[j].fi > tac || cur.se.se + counts[j].se > tbc) continue;
                if (cur.se.fi + counts[j].fi == tac && cur.se.se + counts[j].se == tbc) {
                    ans = (ans + 1) % 1000000007;
                    continue;
                }

                q.push(make_pair(j, ii(cur.se.fi + counts[j].fi, cur.se.se + counts[j].se)));
            }
        }
    }

    cout << ans << endl;

    return 0;
}

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: WRONG ANSWER

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: RUNTIME ERROR

Test 9

Group: 3

Verdict: ACCEPTED

Test 10

Group: 3

Verdict: RUNTIME ERROR

Test 11

Group: 3

Verdict: RUNTIME ERROR

Test 12

Group: 3

Verdict: RUNTIME ERROR

Test 13

Group: 3

Verdict: WRONG ANSWER

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 2, 3

Verdict: RUNTIME ERROR

Test 16

Group: 3

Verdict: RUNTIME ERROR