leetcode题目-9. 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.

思路：负数和末尾是0的数直接返回false，等于0返回true。

判断反转后的数和初始数是否相等，相等即为palindrome number。

class Solution:
    def isPalindrome(self, x: 'int') -> 'bool':
        if x == 0:
            return True
        if x < 0 or x % 10 == 0:
            return False
        m = x
        num = 0
        while m:
            num = num * 10 + m % 10
            m = int(m/10)
        return num == x