UVA 673 Parentheses Balance

Description

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

今天校赛做了个类似于这样的题，比这个难，这里设了个坑，就是空行的时候要输出yes，其它的用栈正常做就行。

LANGUAGE:C++

CODE:

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

bool judge(char a,char b)
{
    if(a=='['&&b==']')return 1;
    if(a=='('&&b==')')return 1;
    return 0;
}

bool left(char a)
{
    if(a=='['||a=='(')return 1;
    return 0;
}

int main()
{
    int cas;
    char s[200];
    cin>>cas;
    getchar();
    while(cas--)
    {
        stack<char>q;
        gets(s);
        if(strcmp(s,"\n")==0)
        {
            cout<<"Yes"<<endl;
            continue;
        }
        for(int i=0;s[i];i++)
        {
            if(q.empty())
            {
                q.push(s[i]);
            }
            else if(!judge(q.top(),s[i]))
            {
                if(left(s[i]))
                q.push(s[i]);
            }
            else q.pop();
        }
        if(q.empty())cout<<"Yes"<<endl;
        else cout<<"No"<<endl;
    }
}