class Solution { public boolean isPalindrome(String s) {
String t = s.replaceAll("[^A-Za-z0-9]", "");
t = t.toLowerCase();
int start =0;
int end=t.length()-1;
while(start<=end){
if(t.charAt(start)!=t.charAt(end)) {
return false;
}
start++;
end--;
}
return true;
}
}