Peli

input/code.cpp: In function 'void solve()':
input/code.cpp:62:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::__cxx11::basic_string<char> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |    for (int i = 0; i < ans.size(); ++i) {
      |                    ~~^~~~~~~~~~~~

#include<bits/stdc++.h>
using namespace std;
 
void init_code(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif 
}

void solve() {
   string s;
   cin >> s;

   int n = s.size();

   vector<pair<int, int>> tmp(26);

   for (int i = 0; i < n; ++i) {
      int x = s[i] - 'A';

      tmp[x].first++;
      tmp[x].second = x;
   }

   priority_queue<pair<int, int>> pq;
   for (auto i : tmp) {
      pq.push(i);
   }

   vector<string> ans;

   while (!pq.empty()) {
      pair<int, int> a = pq.top();
      pq.pop();
      //cout << a.first << ' ' << a.second << '\n';
      
      if (pq.empty()) break;

      pair<int, int> b = pq.top();
      pq.pop();

      if (a.first == 0 || b.first == 0) break;

      string t = "";
      char x = 'A' + a.second, y = 'A' + b.second;
      t += x; t += y;

      int k = b.first;

      for (int i = 0; i < k; ++i) {
         ans.push_back(t);
      }

      pq.push({a.first - b.first, a.second});
      
   }

   cout << ans.size() << '\n';
   for (int i = 0; i < ans.size(); ++i) {
      cout << ans[i] << '\n';
   }
}

int main() {
   init_code();
   solve();
   return 0;
}
 

Test 1

Group: 1, 2

Verdict: WRONG ANSWER

Test 2

Group: 1, 2

Verdict: WRONG ANSWER

Test 3

Group: 2

Verdict: WRONG ANSWER

Test 4

Group: 1, 2

Verdict: WRONG ANSWER

Test 5

Group: 1, 2

Verdict: WRONG ANSWER

Test 6

Group: 2

Verdict: WRONG ANSWER

Test 7

Group: 2

Verdict: WRONG ANSWER

Test 8

Group: 1, 2

Verdict: WRONG ANSWER

Test 9

Group: 2

Verdict: WRONG ANSWER

Test 10

Group: 2

Verdict: WRONG ANSWER