【ruby】leetcode 练习 ：Palindrome Number

给定一个整数x，如果x是回文整数则返回true。

当一个整数向后读和向前读一样时，它就是一个回文数。

Example 1:

Input: x = 121
Output: true
Explanation: 121 reads as 121 from left to right and from right to left.

Example 2:

Input: x = -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: x = 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

方法一：反转字串

def is_palindrome(x)    if x < 0        return false    else        string = x.to_s        if string == string.reverse            return true        else            false        end    endend

方法二 反转数字

def is_palindrome(x)    temp = x    reverseNumber = 0        while temp > 0        rightNumber = temp % 10        reverseNumber = reverseNumber * 10 + rightNumber        temp /= 10    end        if x == reverseNumber        true    else        false    endend