Leetcode 9. Palindrome Number（水）

9. Palindrome Number

Easy

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.


题解：计算倒过来的数是多少，判断两个数是否相等就行

 1 class Solution {
 2 public:
 3     bool isPalindrome(int x) {
 4         if(x < 0 ) return false;
 5         long long lx = 0,rx = x;
 6         while(rx > 0){
 7             lx = lx*10+rx%10;
 8             rx /= 10;
 9         }
10         if(lx==x) return true;
11         else return false;
12     }
13 };

Runtime:  8 ms, faster than 90.24% of C++ online submissions for Palindrome Number.

Memory Usage:  8.2 MB, less than 74.55% of C++ online submissions for Palindrome Number.