UVa 673 - Parentheses Balance

#include <cstdio>
#include <stack>
using namespace std;

int main()
{
//freopen("input.txt", "r", stdin);
stack<char> in;
int n;
char c;
scanf("%d", &n);
getchar();
while (n--)
{
while ((c = getchar()) != '\n')
{
if (!in.empty())
{
if (c == ']' && in.top() == '[' || c == ')' && in.top() == '(')
in.pop();
else
in.push(c);
}
else
in.push(c);
}
if (in.empty())
printf("Yes\n");
else
printf("No\n");
while (!in.empty())
in.pop();
}
return 0;
}