public static void main(String[] agvs){

ValidPalindrome vp = new ValidPalindrome();

System.out.println(vp.isPalindrome("0 man, a plan, a canal: Panam0"));

System.out.println(vp.isPalindrome("race a car"));

}

public boolean isPalindrome(String s){

if(s.length() > 0){

int i = 0, j = s.length() - 1;

while(i < j){

while(!(Character.isDigit(s.charAt(i)) || Character.isAlphabetic(s.charAt(i))) && i < j){

i ++;

}

while(!(Character.isDigit(s.charAt(j)) || Character.isAlphabetic(s.charAt(j))) && i < j){

j --;

}

if(Character.toLowerCase(s.charAt(i)) == Character.toLowerCase(s.charAt(j))){

i ++;

j --;

} else {

return false;

}

}

}

return true;

}

}