题目描述

Determine whether an integer is a palindrome. Do this without extra space.

代码

    public static boolean isPalindrome(int x) {

        if (x < 0) {
            return false;
        }

        if (x >= 0 && x < 10) {
            return true;
        }

        int d = 1;
        while (x / d >= 10) {
            d *= 10;
        }

        while (x != 0) {

            // 若首尾不相等，返回false
            if (x % 10 != x / d) {
                return false;
            }

            x = x % d / 10;
            d /= 100;
        }

        return true;
    }