Monistus

input/code.cpp: In function 'std::string sievenna(std::string)':
input/code.cpp:12:46: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |     for(int i = max(0, (int)s.size()-1-9); i < s.size(); i++){
      |                                            ~~^~~~~~~~~~
input/code.cpp:17:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |             if(i >= s.size()-x){
      |                ~~^~~~~~~~~~~~~
input/code.cpp:28:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   28 |     for(int i = 0; i < s.size(); i++){
      |                    ~~^~~~~~~~~~
input/code.cpp: In function 'std::string haku(std::string)':
input...

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

bool k = false;
int it = 0;

string sievenna(string s){

    // saako sieventää?

    for(int i = max(0, (int)s.size()-1-9); i < s.size(); i++){
        char c = s[i];
        if(isdigit(c)){
            int x = c - '0';

            if(i >= s.size()-x){
                return s;
            }
        }
    }


    // sievennetään.

    string u = "";

    for(int i = 0; i < s.size(); i++){

        char c = s[i];
        int x = c - '0';

        int n = s.size();

        if(isdigit(c)){
            if(i < n-x){
                it++;
                string m = s.substr(i + 1, x);
                k = false;
                //cout << "Lähetä " << m << "\n";
                m = sievenna(m);
                if(!k){
                    s.erase(i + 1, x);
                    s.insert(i + 1, m + m);
                }
                else{
                    s.insert(i + 1, m);
                }
            }
            else{
                k = true;
                u += c;
            }
        }
        else{
            u += c;
        }

    }

    //cout <<u << "\n";

    //cout << "Palauta " << u << "\n";

    return u;
    
}

string haku(string s){
 
    string u = "";
 
    for(int i = 0; i < s.size(); i++){
 
        char c = s[i];
        int x = c - '0';
         
        if(isdigit(c) && i < s.size()-x){
            s.insert(i + 1, haku(s.substr(i + 1, x)));
        }
        else u += c;
        
    }
 
    return u;
 
}




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

    cout << sievenna(s);
    //cout << "\n" << haku(s);

    //cout << (sievenna(s) == haku(s));

    //cout << "\n" << it;

    
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: ACCEPTED

Test 3

Group: 1, 2

Verdict: ACCEPTED

Test 4

Group: 1, 2

Verdict: ACCEPTED

Test 5

Group: 1, 2

Verdict: ACCEPTED

Test 6

Group: 1, 2

Verdict: ACCEPTED

Test 7

Group: 1, 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 12

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 13

Group: 2

Verdict: ACCEPTED

Test 14

Group: 2

Verdict: ACCEPTED