LeetCode 7. Reverse Integer

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

Note:
Assume we are dealing with an environment that 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.

Example 1:
Input: x = 123
Output: 321

Example 2:
Input: x = -123
Output: -321

Example 3:
Input: x = 120
Output: 21

Example 4:
Input: x = 0
Output: 0

Constraints:
-2^31 <= x <= 2^31 - 1

思路:
直接循环读出末尾数据，负数也可以同样处理，如果溢出32位的话就返回0。

Solution:

public class Solution {
    public int reverse(int x) {
        long ret = 0;
        while(x != 0) {
            ret = ret * 10 + x%10;
            x /= 10;
        }
        if(ret > Integer.MAX_VALUE || ret < Integer.MIN_VALUE) {
            return 0;
        }
        return (int)ret;
    }
}