chapter6 数据结构基础之习题 Parentheses Balance

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





用栈模拟匹配括号

#include<iostream>
#include<cstdio>
#include<cstring>
#include<stack>
using namespace std;
int compare(char p,char q)
{
if(p=='('&&q==')') return 1;
if(p=='['&&q==']') return 1;
else return 0;
}
int main()
{
int n,L,flag;
char c[100];

scanf("%d ",&n);
for(int i=0; i<n; i++)
{
stack<char> st;
flag=0;
gets(c);
L=strlen(c);
for(int j=0; j<L; j++)
{

if(c[j]=='('||c[j]=='[') st.push(c[j]);
if(c[j]==')'||c[j]==']')
{
if(st.empty())
{
flag=1;
break;
}
if(compare(st.top(),c[j])) st.pop();
else{
flag=1;
break;
}
}
}
if(flag==1||!st.empty()) cout<<"No"<<endl;
else cout<<"Yes"<<endl;

}
return 0;
}