UVa 673 - Parentheses Balance

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

const int maxn = 150;

int main()
{
#ifdef LOCAL
freopen("in", "r", stdin);
#endif
int n;
char data[150];
stack<char> s;
scanf("%d", &n);
getchar();
while(n--)
{
fgets(data, maxn, stdin);
int len = strlen(data);
if(len == 1)
{
printf("Yes\n");
continue;
}
len--;
while(!s.empty())   s.pop();
for(int i = 0; i < len; i++)
{
if(!s.empty() && ((data[i] == ')' && s.top() == '(') || (data[i] == ']' && s.top() == '[')))
s.pop();
else s.push(data[i]);
}
if(s.empty())   printf("Yes\n");
else printf("No\n");
}
return 0;
}