/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	 public static boolean isPalindrome(String s) {
 
        for(int i = 0, j = s.length() -1; i < s.length()/2; i++, j--){
        	String regex = "^[a-zA-Z0-9]+$";
 
	   	    while(!Character.toString(s.charAt(i)).matches("[A-Za-z0-9]+") && i < s.length()-1){
	   	    	i++;
	   	    }
 
	   	     while(!Character.toString(s.charAt(j)).matches("[A-Za-z0-9]+") && i > 0){
	   	    	j--;
	   	     }
 
            if(Character.toLowerCase(s.charAt(i)) != Character.toLowerCase(s.charAt(j)))
                return false;
             }
           return true;
 
    }
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		System.out.println(isPalindrome("A man, a plan, a canal: Panama"));
	}
}

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