括号配对

Parentheses Balance 

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

    这一题我用了栈，括号配对问题，可能有点复杂了，注意空串也是“Yes”

#include<iostream>#include<cstring>#include<stack>#include<cstdio>using namespace std;stack<char> s;int main(){    char str[130],e;    int n;    while(cin>>n && n)    {       getchar();       while(n--)       {          gets(str);          while(!s.empty())  s.pop();          for(int i=0;i<strlen(str);i++)          {             if(str[i]=='('||str[i]=='[')  s.push(str[i]);             if(str[i]==')')             {                if(!s.empty())                {                   e=s.top();                   if(e=='(') s.pop();                   else break;                }                else s.push(')');             }             if(str[i]==']')             {                if(!s.empty())                {                   e=s.top();                   if(e=='[') s.pop();                   else break;                }                else s.push(']');             }          }          if(s.empty()) cout<<"Yes"<<endl;          else cout<<"No"<<endl;        }    }    return 0;}