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,
© 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
代码
#include<bits/stdc++.h>
using namespace std;
stack<char> str;
int main()
{
//freopen("F:\\1234.txt","r",stdin);
//freopen("F:\\12345.txt","w",stdout);
int t;
cin>>t;
getchar();
while(t--)
{
string s;
getline(cin,s);
if(s.size()==0)
{
cout<<"Yes"<<endl;
continue;
}
int flag=0,flag1=0,cnt1=0,cnt2=0;
for(int i=0;i<s.size();i++)//倒
{
if(s[i]=='('||s[i]=='[')
cnt1++;
else
cnt2++;
if(cnt2>cnt1)
{
flag=1;
break;
}
}
if(flag==1||cnt1!=cnt2)
{
cout<<"No"<<endl;
continue;
}
for(int i=0;i<s.size();i++)//遍历
{
if(s[i]=='('||s[i]=='[')
str.push(s[i]);
else if(!str.empty())
{
int flag2=0;
if((str.top()=='('&&s[i]==')')||(str.top()=='['&&s[i]==']'))
flag2=1;
if(flag2==1)
{
str.pop();
continue;
}
else
{
flag1=1;
break;
}
}
}
if(flag1==0)
cout<<"Yes"<<endl;
else
cout<<"No"<<endl;
}
return 0;
}