Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.
Note
For the purpose of this problem, we define empty string as valid palindrome.
Example
No.1
Input: “A man, a plan, a canal: Panama”
Output: true
No.2
Input: “race a car”
Output: false
Code
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public boolean (String s) {
int start = 0;
int end = s.length() - 1;
while (start < end) {
while (start < end && !Character.isLetterOrDigit(s.charAt(start)))
start++;
while (start < end && !Character.isLetterOrDigit(s.charAt(end)))
end--;
if (Character.toLowerCase(s.charAt(start)) != Character.toLowerCase(s.charAt(end)))
return false;
start++;
end--;
}
return true;
}
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