Palindrome Number
Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.
Example 1:
Input: 121
Output: true
Example 2:
Input: -121
Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.
Example 3:
Input: 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
该题要求判断一个数是否是回文数,主要和Leetcode07联动。若一个数是负数,则肯定不是回文数;否则判断一个数翻转后是否和原来相等即可,需要注意的是翻转后是否以0为开头,
public static boolean isPalindrome(int x) {
if (x < 0 || (x != 0 && x % 10 == 0))
return false;
int rev = 0;
while (x > rev) {
rev = rev * 10 + x % 10;
x = x / 10;
}
return (x == rev || x == rev / 10);
}