Valid Palindrome

最新推荐文章于 2024-01-04 12:53:14 发布

Paul_ZJ

最新推荐文章于 2024-01-04 12:53:14 发布

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分类专栏： LeetCode——坚持每天一题

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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.

Java代码：

public class Solution {
    public boolean isPalindrome(String s) {
        int start =0;
		int end = s.length()-1;
		while(start < end){
			while((s.charAt(start)<'A' || s.charAt(start)>'z' || (s.charAt(start)>'Z' && s.charAt(start)<'a')) && start<s.length()-1 && (s.charAt(start)<'0' || s.charAt(start)>'9'))
				start++;
			while((s.charAt(end)<'A' || s.charAt(end)>'z' || (s.charAt(end)>'Z' && s.charAt(end)<'a')) && end>0  && (s.charAt(end)<'0' || s.charAt(end)>'9'))
				end--;
			if(start < end){
				if(s.charAt(start) == s.charAt(end) ||s.charAt(start)+32 == s.charAt(end) || s.charAt(start)-32 == s.charAt(end)){
					start++;
					end--;
				}else{
					return false;
				}
			}
		}
		return true;
    }
}