栈

A - 栈
Time Limit:3000MS Memory Limit:0KB 64bit IO Format:%lld & %llu

Submit

Status

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
这道题是栈的入门题吧，只是空行也算Yes，要把空行输入进去就要用gets，前面还得加上getchar,防止输入t之后把“\n”当成空行。
代码：

#include<iostream>
#include<cstring>
#include<stack>
#include<stdio.h>
const int maxn=200;
using namespace std;
int main()
{
    int t;
    cin>>t;
    char s[maxn];
    getchar();
    while(t--)
    {
        gets(s);
        if(s[0]=='\n')
        {
            cout<<"Yes"<<endl;
        }
        else
        {
            int m=strlen(s);
            stack<char>q;
            for(int i=0;i<m;i++)
            {
                if(q.empty())
                    q.push(s[i]);
                else if((q.top()=='('&&s[i]==')')||(q.top()=='['&&s[i]==']'))
                    q.pop();
                else q.push(s[i]);
            }
            if(q.empty())
                cout<<"Yes"<<endl;
            else cout<<"No"<<endl;
        }
    }
    return 0;
}