Palindromi

#include<iostream>
#include<cmath>
#include<algorithm>
#include<string>

using namespace std;

typedef long long ll;
typedef long double ld;

ll n,k;
string s;
void solve(){
    if(k%2==0){
        for(ll i=1;i<=k/2;i++){
            if(i%2==1)s+="d";
            if(i%2==0)s+="e";
        }
        cout<<s;
        for(ll i=s.size()-1;i>=0;i--){
            cout<<s[i];
        }
    }
    else if(k%2==1){
        for(ll i=1;i<=k;i++){
            if(i%2==1)cout<<"d";
            if(i%2==0)cout<<"e";
        }
    }
}
int main(){
    cin>>n>>k;
    ll d=n-k;
    for(ll i=1;i<=d;i++){
        if(i%3==1)cout<<"a";
        if(i%3==2)cout<<"b";
        if(i%3==0)cout<<"c";
    }
    solve();
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED