LeetCode Q125: Valid Palindrome

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.

	class Solution {
	public:
	bool isPalindrome(string s) {
	if(s.length()==0)
	return true;
	int p0=0;
	int p1=s.length()-1;
	int dis='a'-'A';
	while(p0<=p1){
	while(!((s[p0]>='a'&&s[p0]<='z')||(s[p0]>='A'&&s[p0]<='Z')||(s[p0]>='0' && s[p0]<='9'))&&p0<=s.length()-1)
	{p0++;}
	while(!((s[p1]>='a'&&s[p1]<='z')||(s[p1]>='A'&&s[p1]<='Z')||(s[p1]>='0' && s[p1]<='9'))&&p1>=0)
	{p1--;}
	if(p0>p1)
	break;
	s[p0]=s[p0]>='a'? s[p0]-dis:s[p0];
	s[p1]=s[p1]>='a'? s[p1]-dis:s[p1];
	if(s[p0]!=s[p1])
	return false;
	p0++;
	p1--;
	}
	return true;
	}
	};

view raw Q129ValidPalindrome.cpp hosted with ❤ by GitHub