Problem Description: Palindrome String
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package com.gauk;
public class Solution {
/*
* Given a string, determine if it is a palindrome, considering only
* alphanumeric characters and ignoring cases.
*
* Example:
*
* "A man, a plan, a canal: Panama" is a palindrome.
*
* "race a car" is not a palindrome.
*
* Return 0 / 1 ( 0 for false, 1 for true ) for this problem
*/
public static void main(String[] args) {
System.out.println(new Solution().isPalindrome("race a car"));
}
public int isPalindrome(String A) {
//replace all non-alphanumeric characters to white space and change them to lower case
A = A.replaceAll("[^A-Za-z0-9]", "").toLowerCase();
//loop through the elements and check if the are equal. We can do it only for half the elements to reduce time.
for(int i=0; i<A.length(); i++) {
if(A.charAt(i) != A.charAt(A.length()-i-1)) {
return 0;
}
}
return 1;
}
}