You are given a string consisting of parentheses () and []. A string of this type is said to be correct:
- if it is the empty string
- 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
括号比對算法
#include <cstdio>
#include <cstring>
#include <stack>
using namespace std;
int main()
{
int n;
scanf ("%d",&n);
getchar();
while (n--)
{
bool flag=true;
stack <char> s;
while (!s.empty())
s.pop();
char a[1000]={0};
gets(a);
int l=strlen(a);
//Ñ»·Ìõ¼þ²»ÒªÐ´³Éa[i]!=0
for (int i=0;i<l;i++)
{
if (a[i]=='(' || a[i]=='[')
s.push(a[i]);
else if (a[i]==')' || a[i]==']')
{
if (!s.empty() && a[i]==')' && s.top()=='(')
s.pop();
else if (!s.empty() && a[i]==']' && s.top()=='[')
s.pop();
else
{
flag=false;
break;
}
}
}
if (flag&&s.empty())
{
printf ("Yes\n");
}
else
{
printf ("No\n");
}
}
return 0;
}