UVA - 673

You are given a string consisting of parentheses () and []. A string of this type is said to be correct:(a) if it is the empty string(b) if A and B are correct, AB is correct,(c) if A is correct, (A) and [A] is correct.Write a program that takes a sequence of strings of this type and check their correctness. Yourprogram can assume that the maximum string length is 128.

Input

The file contains a positive integer n and a sequence of n strings of parentheses ‘()’ and ‘[]’, one stringa line.

Output

A sequence of ‘Yes’ or ‘No’ on the output file.

Sample Input

3

([])(([()])))([()[]()])()

Sample Output

Yes

No

Yes

#include<iostream>
#include<cstdio>
#include<cstring>
#include<stack>
using namespace std;
int main()
{
	int T;
	scanf("%d ", &T);
	while(T--)
	{
		char f[150];
		stack<char>ch;
		int len = 0, flag = 1;
		while((f[len] = getchar()) != '\n')
		{
			++len;
		}
		for(int i = 0; i < len; ++i)
		{
			if(f[i] == '(' || f[i] == '[')
			{
				ch.push(f[i]);
			}
			else if(f[i] == ')')
			{
				if(ch.empty())
				{
					flag = 0;
					break;
				}
				if(ch.top() == '(')
					ch.pop();
			}
			else if(f[i] == ']')
			{
				if(ch.empty())
				{
					flag = 0;
					break;
				}
				if(ch.top() == '[')
					ch.pop();
			}
		}
		if(ch.empty() && flag)
			cout << "Yes" << endl;
		else
			cout << "No" << endl;
	}
}