Sukat

input/code.cpp: In function 'int main()':
input/code.cpp:19:9: warning: unused variable 'last' [-Wunused-variable]
   19 |     int last = -1;
      |         ^~~~
input/code.cpp:20:10: warning: unused variable 'g' [-Wunused-variable]
   20 |     bool g = true;
      |          ^

#include <bits/stdc++.h>

using namespace std;

int main() {
    const int Z = 30;
    string str;
    cin >> str;
    
    vector<int> sukat;

    for (int i = 0; i < (int) str.length(); i++) {
        sukat.push_back((int) str[i]);
    }
    sort(sukat.begin(), sukat.end());

    map<int, int> m;

    int last = -1;
    bool g = true;
    for (int i = 0; i < (int) sukat.size(); i++) {
        //cout << sukat[i] << " ";
        int c = ((int) sukat[i]) - 65;
        if (m.count(c) == 0) {
            m[c] = 0;
        }
        m[c] += 1;
        c++;
    }
    
    int c = sukat.size();

    //cout << s1[0] << s1[1] << s1[2] << endl;
    //cout << s2[0] << s2[1] << s2[2] << endl;

    vector<pair<char, char>> res;

    while (c > 0) {
        int max1 = -1;
        int index1 = -1;
        int max2 = -1;
        int index2 = -1;
        for (int i = 0; i < Z; i++) {
            int c = m[i];
            if (c > max1) {
                max2 = max1;
                index2 = index1;
                max1 = c;
                index1 = i;
            } else if (c > max2) {
                max2 = c;
                index2 = i;
            }
        }

        //cout << (char) (index1 + 65) << " " << m[index1] << "   " << (char) (index2 + 65) << " " << m[index2] << endl;

        //cout << "i1: " << index1 << " i2: " << index2 << endl;

        if (index1 == -1 || index2 == -1) {
            break;
        }

        int a = min(max1, max2);
        m[index1] -= a;
        m[index2] -= a;
        c -= a * 2;

        if (a == 0) {
            break;
        }
        
        for (int i = 0; i < a; i++) {
            res.push_back({ (char) (index1 + 65), (char) (index2 + 65)});
        }
    }

    cout << res.size() << "\n";
    for (int i = 0; i < (int) res.size(); i++) {
        cout << res[i].first << res[i].second << "\n"; 
    }
}

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: ACCEPTED

Test 7

Group: 1, 2, 3

Verdict: ACCEPTED

Test 8

Group: 2, 3

Verdict: ACCEPTED

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