Sukat

input/code.cpp: In function 'int main()':
input/code.cpp:23:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |     if (a[0].F<s.size()/2) c=s.size()/2;
      |         ~~~~~~^~~~~~~~~~~

#include<bits/stdc++.h>
using namespace std;
#define N ((int)(2e5+5))
#define F first
#define S second

string s;
int c;
pair<int,char> a[30];

int main() {
    cin.tie(0)->sync_with_stdio(false);
    cout.tie(0);

    cin>>s;
    for (int i=0;i<30;++i) a[i].S='A'+i;
    for (char i : s) a[(i-'A')].F++;
    sort(a,a+30);
    reverse(a,a+30); 
    //for (auto i:a) cout<<i.F<<' '<<i.S<<", ";
    //cout<<endl;
    int o1=0,o2=1;
    if (a[0].F<s.size()/2) c=s.size()/2;
    else c=min(a[0].F,((int)(s.size()))-a[0].F);
    cout<<c<<'\n';
    for (int i=0;i<c;++i) {
        while (o1<29 && !a[o1].F) o1++;
        o2=o1+1;
        while (o2<30 && !a[o2].F) o2++;
        if(a[o1].F>0 && a[o2].F>0)
            cout<<a[o1].S<<a[o2].S<<'\n';
        a[o1].F--;
        a[o2].F--;
    }
}

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