回文数串

public boolean isPalindrome(String s) {
s = s.replaceAll("[^a-zA-Z0-9]", "").toLowerCase();

char[] chars = s.toCharArray();

int i = 0;
int j = chars.length - 1;

while (i < j) {
if (chars[i] == chars[j]) {
i++;
j--;
} else {
return false;
}
}

return true;
}