Pakkaus

#include <iostream>
#include <string>
#include <vector>
#include <ctype.h>
#include <stdlib.h>
#define ull unsigned long long

using namespace std;

int main(void)
{
    string s;
    cin >> s;

    vector<ull> n;
    vector<string> str;

    ull n_l = 0;
    ull n_h = 0;
    ull s_l = 0;
    ull s_h = 0;

    for (ull i = 1; i < s.length(); i++)
    {
        // move n upper bound
        if (isdigit(s[i]) && isdigit(s[i-1]))
        {
            n_h = i;
        }
        else if (!isdigit(s[i]) && isdigit(s[i-1]))
        {
            // store s lower bound
            s_l = i;
            s_h = i;

            // save number
            string tmp;
            for (ull j = n_l; j <= n_h; j++)
            {
                tmp+=s[j];
            }
            n.push_back(atoi(tmp.c_str()));

        }
        else if (!isdigit(s[i]) && !isdigit(s[i-1]))
        {
            s_h = i;
        }
        else if (!isdigit(s[i-1]) && isdigit(s[i]))
        {
            n_l = i;
            n_h = i;
            
            // save string 
            string tmp;
            for (ull j = s_l; j <= s_h; j++)
            {
                tmp+=s[j];
            }
            str.push_back(tmp);
        }

    }
    string tmp;
    for (ull j = s_l; j <= s_h; j++)
    {
        tmp+=s[j];
    }
    str.push_back(tmp);

    for (ull i = 0; i < n.size(); i++)
    {
        for (ull j = 0; j < n[i]; j++)
        {
            cout << str[i];
        }
    }
    cout << endl;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED