UVa 673 Parentheses Balance

  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

---

Miguel Revilla 
2000-08-14

括号匹配问题，就是摸拟一个栈的操作：‘(’和‘[’相当于入栈操作，‘)’和‘]’相当于出栈操作

注意处理完一行之后栈必需为空才能输出Yes

#include<iostream>
#include<cstdio>

using namespace std;

int main()
{
    int kase;

    scanf("%d",&kase);
    getchar();

    while(kase--)
    {
        int f=0;
        char s[150],Stack[150];
        bool finished=false,yes=true;

        gets(s);

        for(int i=0;(!finished)&&s[i]!='';i++)
        {
            switch(s[i])
            {
                case '(':Stack[f++]='(';break;
                case '[':Stack[f++]='[';break;
                case ')':if(f>0&&Stack[f-1]=='(')
                            f--;
                         else
                         {
                             finished=true;
                             yes=false;
                         }
                         break;
                case ']':if(f>0&&Stack[f-1]=='[')
                            f--;
                         else
                         {
                             finished=true;
                             yes=false;
                         }
                         break;
            }
        }

        printf("%s
",yes&&(f==0)?"Yes":"No");
    }

    return 0;
}