Merkkijonot

input/code.cpp: In function 'long long int dfs(int, std::vector<bool>, int, int)':
input/code.cpp:17:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |     for (int i = cur + 1; i < counts.size(); i++) {
      |                           ~~^~~~~~~~~~~~~~~
input/code.cpp: In function 'int main()':
input/code.cpp:59:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |     for (int i = 0; i < counts.size() - 1; i++){
      |                     ~~^~~~~~~~~~~~~~~~~~~

#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;

ll dfs(int cur, vector<bool> vis, int ac, int bc) {
    if (vis[cur]) return 0;
    vis[cur] = true;
    ll ans = 0;

    for (int i = cur + 1; i < counts.size(); i++) {
        if (vis[i] || cur == i) continue;

        if (ac + counts[i].fi > tac || bc + counts[i].se > tbc) continue;
        if (ac + counts[i].fi == tac && bc + counts[i].se == tbc) {
            ans += 1;
            ans %= 1000000007;
            continue;
        }
        
        ans = (ans + dfs(i, vis, ac + counts[i].fi, bc + counts[i].se)) % 1000000007;
    }

    return ans;
}

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++){
        ans += dfs(i, vector<bool>(counts.size()), counts[i].fi, counts[i].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: TIME LIMIT EXCEEDED

Test 9

Group: 3

Verdict: ACCEPTED

Test 10

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 11

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 12

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 13

Group: 3

Verdict: WRONG ANSWER

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 2, 3

Verdict: TIME LIMIT EXCEEDED

Test 16

Group: 3

Verdict: TIME LIMIT EXCEEDED