Sukat

input/code.cpp: In function 'int main()':
input/code.cpp:3:37: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    3 | #define forn(i, n) for (int i = 0; i<n; i++)
      |                                     ^
input/code.cpp:32:5: note: in expansion of macro 'forn'
   32 |     forn(i, v.size()) {
      |     ^~~~

#include <bits/stdc++.h>

#define forn(i, n) for (int i = 0; i<n; i++)
#define FOR(i, k, n) for (int i = k; i < n; i++)
#define N 1<<17
#define pb push_back
typedef long long ll;
using namespace std;

int n;
string s;
string v;

int main() {

    cin >> s;
    n = s.size();

    forn(i, n) {
        if (s[i] == '!') continue;

        forn(j, n) {
            if (s[j] != '!' && s[j] != s[i]) {
                v.pb(s[i]); 
                v.pb(s[j]);
                s[j] = '!'; s[i] = '!';
                break;
            }
        }
    }
    cout << v.size()/2 << endl;
    forn(i, v.size()) {
        cout << v[i];
        if (i&1) cout << endl;
    } 
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: WRONG ANSWER

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: 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: ACCEPTED

Test 15

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 16

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 17

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 18

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 19

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 20

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 21

Group: 3

Verdict: TIME LIMIT EXCEEDED