Monistus

#include <bits/stdc++.h>

using namespace std;

string processString(const string &s)
{
    string result = s;

    while (any_of(result.begin(), result.end(), ::isdigit))
    {
        size_t index = 0;
        while (index < result.length())
        {
            if (isdigit(result[index]))
            {
                int digit = result[index] - '0';
                result.erase(index, 1);
                result.insert(index, result.substr(index, digit));
                index += digit;
            }
            else
            {
                ++index;
            }
        }
    }

    return result;
}

int main()
{
    string s;
    cin >> s;
    cout << processString(s) << endl;

    return 0;
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: ACCEPTED

Test 3

Group: 1, 2

Verdict: WRONG ANSWER

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: WRONG ANSWER

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