Monistus

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
#define M 1e9+7

int main(){
    string txt,ntxt;
    cin >> txt;

    ll n;

    for(int i=0; i < (int)(txt.size()); i++){
        if(isdigit(txt[i])){
            n = txt[i];
            txt.substr(i,1);
            ntxt = txt.substr(i,n);
            for(int j=0; j < n; j++){
                txt.insert(i,ntxt);
            }
        }else{}
    }
    cout << txt;
}

Test 1

Group: 1, 2

Verdict: TIME LIMIT EXCEEDED

Test 2

Group: 1, 2

Verdict: TIME LIMIT EXCEEDED

Test 3

Group: 1, 2

Verdict: TIME LIMIT EXCEEDED

Test 4

Group: 1, 2

Verdict: TIME LIMIT EXCEEDED

Test 5

Group: 1, 2

Verdict: TIME LIMIT EXCEEDED

Test 6

Group: 1, 2

Verdict: TIME LIMIT EXCEEDED

Test 7

Group: 1, 2

Verdict: TIME LIMIT EXCEEDED

Test 8

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 11

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 12

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 13

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 14

Group: 2

Verdict: TIME LIMIT EXCEEDED