Merkkijonot

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair <ll, ll> pl;
typedef vector <pl> vpl;
const ll modd = 1e9 + 7;
 
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
 
    ll n, i, j, l, a, b, sa = 0, sb = 0, ca, cb, ans = 0;
    string s;
    cin >> n;
    vpl p(n);
    for(i = 0; i < n; i++)
    {
        a = b = 0;
        cin >> s;
        l = s.length();
        for(j = 0; j < l; j++)
            if(s[j] == 'a')
                a++;
            else
                b++;
        p[i] = {a, b};
        sa += a;
        sb += b;
    }
    if(sa % 2 != 0 || sb % 2 != 0)
    {
        cout << 0;
        return 0;
    }
    sa /= 2;
    sb /= 2;
 
    n = 1 << n;
 
    for(i = 0; i < n; i++)
    {
        j = ca = cb = 0;
        while((1 << j) <= i)
        {
            if((1 << j) & i)
            {
                ca += p[j].first;
                cb += p[j].second;
            }
            j++;
        }
        if(ca == sa && cb == sb)
            ans++;
    }
    cout << ans;
    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: 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: WRONG ANSWER

Test 9

Group: 3

Verdict: ACCEPTED

Test 10

Group: 3

Verdict: WRONG ANSWER

Test 11

Group: 3

Verdict: WRONG ANSWER

Test 12

Group: 3

Verdict: WRONG ANSWER

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 2, 3

Verdict: WRONG ANSWER

Test 16

Group: 3

Verdict: WRONG ANSWER