LeetCode 7. Reverse Integer （倒转数字）

Given a 32-bit signed integer, reverse digits of an integer.

Example 1:

Input: 123
Output:  321

Example 2:

Input: -123
Output: -321

Example 3:

Input: 120
Output: 21

Note:
Assume we are dealing with an environment which could only hold integers within the 32-bit signed integer range. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

Java Solution:

Runtime beats 80.84% 

完成日期：06/12/2017

关键词：reverse int

关键点：% 10; / 10

 1 class Solution 
 2 {
 3     public int reverse(int x) 
 4     {
 5         int res = 0;
 6            
 7         while(x != 0)
 8         {
 9             int tail = x % 10;
10             int newRes = res * 10 + tail;
11             
12             if((newRes - tail) / 10 != res) // check overflow
13                 return 0;
14             
15             res = newRes;
16             x = x / 10;
17         }
18         
19     
20         return res;
21     }
22 }

参考资料：https://discuss.leetcode.com/topic/6104/my-accepted-15-lines-of-code-for-java

LeetCode 题目列表 - LeetCode Questions List

题目来源：https://leetcode.com/