A - 栈

Description

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

思路：

使用栈模拟就好

#include"iostream"
#include"cstring"
#include"stdio.h"
using namespace std;
int main()
{
int  T;
cin>>T;
getchar();

while(T--)
{
char a[130];

gets(a);

char stack[130];
int top=0;

int len=strlen(a);
bool ok=true;

for(int i=0;i<len;i++)
{

if(a[i]==‘(‘||a[i]==‘[‘)
{
top++;
stack[top]=a[i];
}

if(a[i]==‘)‘)
{
if(stack[top]!=‘(‘) {ok=false;
break;
}
top--;
}

if(a[i]==‘]‘)
{
if(stack[top]!=‘[‘) {ok=false;
break;
}
top--;
}

}
if(ok&&top==0) cout<<"Yes"<<endl;        //必须判断栈是否为空，因为你必须保证左边的括号不会多了
else   cout<<"No"<<endl;
}
	return 0;
}