Monistus

#include <iostream>
#include <deque>
using namespace std;


deque<char> Boo(deque<char> s)
{
    int loo = 0;
    while (loo < (int)s.size())
    {
        if (isdigit(s[loo]))
        {
            int cn = s[loo] - '0';

            if ((int)s.size() - loo - 1 < cn) return s;

            deque<char> soo(s.begin() + loo + 1, s.begin() + loo + 1 + cn);
            soo = Boo(soo);
            s.insert(s.begin() + loo + 1, soo.begin(), soo.end());
            s.erase(s.begin() + loo);
        }
        else
        {
            loo++;
        }
    }

    return s;
}



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

    string soho;
    cin >> soho;

    deque<char> charles(soho.begin(), soho.end());

    charles = Boo(charles);

    for (char leclerc : charles)
        cout << leclerc;

    return 0;
}

// >
// 82silisko
// 2silisko2silisko
// sisilisko2silisko
// sisiliskosisilisko
// sisiliskosisilisko


// mis3si1pi
// missi1si1pi
// mississi1pi
// mississippi

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: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

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