uva 673 Parentheses Balance

 

Parentheses Balance

You are given a string consisting of parentheses () and []. A string of this type is said to becorrect:

(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 ofn strings of parentheses () and [], one string a line.

Output

A sequence of Yes or No on the output file.

Sample Input

3

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

 Sample Output

YesNoYes

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Miguel Revilla
2000-08-14题意：如果有一个'（'那么就要有一个）与它匹配，如果有一个'['那么就要有一个']'与它匹配.。如果都满足，输出”YES“，else 输出”NO“.思路；建立一个栈，左括号’[‘,'('都入栈，右括号')',']'都出栈依次进行下去，如果栈为空，则满足条件，输出“YES”,如果不满足条件，则输出”NO“。代码：

#include<cstdio>#include<stack>using namespace std;int main(){    int n;    scanf("%d",&n);        getchar();        while(n--)        {            char a[130];            stack<char> s;            gets(a);            int flag=0;    for(int i=0;a[i]!='\0';i++)        {            if(a[i]=='('||a[i]=='[')                 s.push(a[i]);            else if(a[i]==')')            {                if(!s.empty()&&s.top()=='(')   s.pop();                else                    {flag=1;break;}            }            else if(a[i]==']')            {                if(!s.empty()&&s.top()=='[')                    s.pop();                else {flag=1;break;}            }        }        if(flag||!s.empty())   printf("No\n");        else printf("Yes\n");        }    return 0;}