/*
Given a
string, determine
if it
is a palindrome, considering only alphanumeric characters
and ignoring cases.
For example,
"A man, a plan, a canal: Panama" is a palindrome.
"race a car" is not a palindrome.
Note:
Have you consider that the
string might be
empty? This
is a good question
to ask during an interview.
For the purpose of this problem, we define
empty string as valid palindrome.
两个指针问题
*/
#include <iostream>
#include <
string>
using namespace std;
class Solution {
public:
bool isPalindrome(
string s) {
int left=
0,
right=s.size()-
1;
while(
left<
right)
{
while(
left<
right && isalnum(s[
left]) ==
false)
left++;
while(
left<
right && isalnum(s[
right]) ==
false )
right--;
if(
left>=
right) return
true;
if(toupper(s[
left]) != toupper(s[
right]))
return
false;
left++,
right--;
}
return
true;
}
};
int main()
{
Solution mys;
string s=
"canal: Panama";
cout<<mys.isPalindrome(s)<<endl;
return
0;
}
