Parentheses Balance-栈

Parentheses Balance

Time Limit:3000MS     Memory Limit:0KB     64bit IO Format:%lld & %llu

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. Your program 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 string a line.

Output 

A sequence of  Yes  or  No  on the output file.

Sample Input 

3
([])
(([()])))
([()[]()])()

Sample Output 

Yes
No
Yes

代码：

#include<iostream>  
#include<deque>  
#include<algorithm>  
#include<cstdio>  
#include<stack>  
#include<string>  
using namespace std;  
char f(char c)  
{  
    if(c==')')return '(';  
    if(c==']')return '[';  
    return 0;  
}  
bool judge(const string& s)  
{  
    stack<char>st;  
    st.push('0');  
    for(int i=0;i<s.size();i++)  
    {  
        if(st.top()!=f(s[i]))  
        st.push(s[i]);  
        else st.pop();  
    }  
    return st.size()==1;  
}  
  
  
int main()  
{  
    int n;  
    scanf("%d",&n);  
    string s;  
    getchar();  
    while(n--)  
    {  
        getline(cin,s);  
        if(s.size()==0||judge(s))cout<<"Yes"<<endl;  
        else cout<<"No"<<endl;  
    }  
    return 0;  
}