Monistus

#include <bits/stdc++.h>

using namespace std;

int main() {
    char c;
    string cs;
    int cn;
    string m;
    string l,r;
    cin >> r;
    l = "";
    while (r.size() != 0) {
        c = r[0];
        cs = r[0];
        if (c >= 48 and c <= 57) {
            m = "";
            cn = stoi(cs);
            for (int i = 1; i <= cn; i++) {
                m = m+r[i];
            }
            r = m+r.substr(1);
        }
        else {
            l = l+r[0];
            r = r.substr(1);
        }
    }
    cout << l;
}

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: 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