백준 1662 압축 / C++

#include <iostream>
#include <string>
#include <stack>
using namespace std;
#define MAX 55
string s;
int visited[MAX];
stack<int> st;
int func(int start, int end)
{
	int result = 0;
	for (int i = start; i < end; i++)
	{
		if (s[i] == '(')
		{
			int K = s[i - 1] - '0';
			result += K * func(i + 1, visited[i]) - 1;
			i = visited[i];
			continue;
		}
		result++;
	}
	return result;
}

int main(void)
{
	cin >> s;

	for (int i = 0; i < s.length(); i++)
	{
		if (s[i] == '(')
		{
			st.push(i);
		}
		else if (s[i] == ')')
		{
			visited[st.top()] = i;

			st.pop();
		}
	}

	cout << func(0, s.length()) << "\n";

	return 0;
}