[leetcode] 7. Reverse Integer

原题:

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 store integers within the 32-bit signed integer range: [−231,  231 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

思路:

用long型保存反转结果,进行溢出判断.

c++代码实现:

class Solution {
public:
    int reverse(int x) {
	long  res = 0;
	while(x){
		res = res*10 + x%10;
		x = x/10; 
	}
	return  (res >INT_MAX || res <INT_MIN)?0:res; 
    }
};