Sukat

#include<bits/stdc++.h>
using namespace std;
using ll = long long;




int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);

    //fstream input;
    //input.open("output.txt");


 
    unordered_map<char, int> m;
    char c;
    while(cin >> c){
        m[c]++;
    }
 



    vector<pair<ll, char>> v;
    for(auto u : m) v.push_back({u.second, u.first});

    //for(auto u : v) cout << u.first << " " << u.second << "\n";

    vector<string> w;

    while(true){

        sort(v.rbegin(), v.rend());

        auto eka = v[0];
        auto toka = v[1];

        if(eka.first == 0 || toka.first == 0) break;

        string z = "";
        z += eka.second;
        z += toka.second;
        w.push_back(z);

        v[0] = {eka.first - 1, eka.second};
        v[1] = {toka.first - 1, toka.second};


    }

    cout << w.size() << "\n";
    for(string b : w) cout << b << "\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: ACCEPTED

Test 14

Group: 2, 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED

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: ACCEPTED

Test 21

Group: 3

Verdict: ACCEPTED