Monistus

#include <bits/stdc++.h>
using namespace std;
 
int main() {
    string s, ans = "";
    cin >> s;
    while (true) {
        ans = "";
        for (int i = 0; i < (int) s.size(); ++i) {
            if (isdigit(s[i])) {
                string s2 = "";
                int j = i+1;
                for (; j <= (s[i]-'0')+i; ++j) 
                    s2 += s[j];
                ans += s2;
                ans += s2;
                i = j-1;
            }
            else
                ans += s[i];
        }       
        s = ans;
        bool ok = 1;
        for (int i = 0; i < (int) s.size(); ++i) 
            if (isdigit(s[i]))
                ok = 0;
        if (ok)
            break;
    }
    cout << s << '\n';
}

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: WRONG ANSWER

Test 6

Group: 1, 2

Verdict: WRONG ANSWER

Test 7

Group: 1, 2

Verdict: WRONG ANSWER

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 11

Group: 2

Verdict: ACCEPTED

Test 12

Group: 2

Verdict: ACCEPTED

Test 13

Group: 2

Verdict: ACCEPTED

Test 14

Group: 2

Verdict: ACCEPTED