Sukat

input/code.cpp: In function 'void solve()':
input/code.cpp:59:22: 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]
   59 |    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 
}
 
bool cmp (pair<int, int> a, pair<int, int> b) {
   return a.second < b.second;
}
 
void solve() {
   string s;
   cin >> s;
 
   int n = s.size();
 
   sort(s.begin(), s.end());
 
   vector<pair<int, int>> a(26);
   for (int i = 0; i < n; ++i) {
      int x = s[i] - 'A';
      a[x].first = x;
      a[x].second++;
   }
 
   sort(a.rbegin(), a.rend(), cmp);
 
   vector<string> ans;
 
   int i = 0, j = 26 - 1;
   while (i != j) {
      if (a[i].second <= 0) {
         i++;
         continue;
      }
 
      if (a[j].second <= 0) {
         j--;
         continue;
      }
 
      a[i].second--;
      a[j].second--;
      
      string t = "";
      char x = 'A' + a[i].first, y = 'A' + a[j].first;
      t += x; t += y;
 
      ans.push_back(t);
   }
 
   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, 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: 1, 2, 3

Verdict: ACCEPTED

Test 6

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 7

Group: 1, 2, 3

Verdict: ACCEPTED

Test 8

Group: 2, 3

Verdict: WRONG ANSWER

Test 9

Group: 2, 3

Verdict: ACCEPTED

Test 10

Group: 2, 3

Verdict: ACCEPTED

Test 11

Group: 2, 3

Verdict: ACCEPTED

Test 12

Group: 2, 3

Verdict: ACCEPTED

Test 13

Group: 2, 3

Verdict: WRONG ANSWER

Test 14

Group: 2, 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: WRONG ANSWER

Test 16

Group: 3

Verdict: ACCEPTED

Test 17

Group: 3

Verdict: ACCEPTED

Test 18

Group: 3

Verdict: ACCEPTED

Test 19

Group: 3

Verdict: ACCEPTED

Test 20

Group: 3

Verdict: WRONG ANSWER

Test 21

Group: 3

Verdict: ACCEPTED