Monistus

input/code.cpp: In function 'int main()':
input/code.cpp:15:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |         for (int i = 0; i < v.size(); i++) s.push(v[i]);
      |                         ~~^~~~~~~~~~

#include <iostream>
#include <stack>
#include <algorithm>

using namespace std;

int k;
string v;
string z;
stack<char> s;

int main() {
	cin >> v;
	reverse(v.begin(), v.end());
	for (int i = 0; i < v.size(); i++) s.push(v[i]);

	k = 0;
	while (!s.empty()) {
		char x = s.top();
		if ((int)x - 48 > 0 && (int)x - 48 <= 9) k = (int)x - 48;
		if (k == 0) {
			z += x;
			s.pop();
		}
		else {
			s.pop();
			string a;
			for (int i = 0; i < k; i++) {
				a += s.top();
				s.pop();
			}
			for (int i = 0; i < 2; i++) {
				for (int j = k - 1; j >= 0; j--) {
					s.push(a[j]);
				}
			}
			k = 0; 
		}
	}
	cout << z;
}

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: ACCEPTED

Test 12

Group: 2

Verdict: ACCEPTED

Test 13

Group: 2

Verdict: ACCEPTED

Test 14

Group: 2

Verdict: ACCEPTED