Monistus

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

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);

    vector <string> s(2);
    ll l, i, j = 0, d;

    cin >> s[j];
    l = s[j].length();
    for(i = 0; i < l; i++)
        if(s[j][i] < 'a')
        {
            d = s[j][i] - '0';
            s[1 - j] = s[j].substr(0, i) + s[j].substr(i + 1, d) + s[j].substr(i + 1, d) + s[j].substr(i + 1 + d, l - i - d - 1);
            l += d - 1;
            s[j].erase(s[j].begin() + i);
            i--;
            //cout << s[1 - j] << "\n";
            //cout << l << " ";
            j = 1 - j;
        }
    cout << s[j];

    return 0;
}

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