Sukat

input/code.cpp: In function 'int main()':
input/code.cpp:56:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<char, char> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |     for (int i = 0; i < combs.size(); ++i) {
      |                     ~~^~~~~~~~~~~~~~
input/code.cpp:11:8: warning: unused variable 'size' [-Wunused-variable]
   11 |     ll size = in.size();
      |        ^~~~

#include "bits/stdc++.h"

typedef long long ll;

using namespace std;

int main() {
    // palindrome
    string in;
    cin >> in;
    ll size = in.size();
    //cout << size << endl;
    deque<pair<char, int>> q;
    map<char, int> mp;
    for (char& c : in) {
        mp[c] += 1;
    }
    for (auto a : mp) {
        q.push_back(a);
    }

    vector<pair<char, char>> combs;


    while (!q.empty()) {
        pair<char, int> p = q.front();
        char c = p.first;
        int n = p.second;
        //cout << c << ": " << n << endl;
        /*if(n >= floor(size/2)) {
            max = floor(mp.size()-1);
        }*/
        q.pop_front();
        bool front = false;
        while (n > 0) {
            front = !front;
            auto &b = front ? q.front() : q.back();
            //cout << "g  " << b.first << ": " << b.second << endl;
            
            combs.push_back(make_pair(c, b.first));
            n -= 1;
            b.second -= 1;

            if(b.second <= 0) {
                if(front)
                    q.pop_front();
                else 
                    q.pop_back();
            }
            if(q.empty()) {
                break;
            }
        }
    }
    cout << (combs.size()) << endl;
    for (int i = 0; i < combs.size(); ++i) {
        cout << combs[i].first << combs[i].second << endl;
    }
    //cout << max << endl;
    return 0;
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: RUNTIME ERROR

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: RUNTIME ERROR

Test 5

Group: 1, 2, 3

Verdict: ACCEPTED

Test 6

Group: 1, 2, 3

Verdict: RUNTIME ERROR

Test 7

Group: 1, 2, 3

Verdict: ACCEPTED

Test 8

Group: 2, 3

Verdict: RUNTIME ERROR

Test 9

Group: 2, 3

Verdict: RUNTIME ERROR

Test 10

Group: 2, 3

Verdict: WRONG ANSWER

Test 11

Group: 2, 3

Verdict: WRONG ANSWER

Test 12

Group: 2, 3

Verdict: WRONG ANSWER

Test 13

Group: 2, 3

Verdict: WRONG ANSWER

Test 14

Group: 2, 3

Verdict: RUNTIME ERROR

Test 15

Group: 3

Verdict: WRONG ANSWER

Test 16

Group: 3

Verdict: WRONG ANSWER

Test 17

Group: 3

Verdict: RUNTIME ERROR

Test 18

Group: 3

Verdict: WRONG ANSWER

Test 19

Group: 3

Verdict: WRONG ANSWER

Test 20

Group: 3

Verdict: RUNTIME ERROR

Test 21

Group: 3

Verdict: RUNTIME ERROR