LeetCode Problem
125. Valid Palindrome
Link to LeetCode
A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers.
Given a string s, return true if it is a palindrome, or false otherwise.
Input: s = "A man, a plan, a canal: Panama"
Output: true
Explanation: "amanaplanacanalpanama" is a palindrome.
class Solution {
public boolean isPalindrome(String s) {
int i=0, j=s.length()-1;
while (i< j) {
if (!Character.isLetterOrDigit(s.charAt(i))) {
i++;
continue;
}
if (!Character.isLetterOrDigit(s.charAt(j))) {
j--;
continue;
}
if (Character.toLowerCase(s.charAt(i)) != Character.toLowerCase(s.charAt(j))) {
return false;
}
i++;
j--;
}
return true;
}
}