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:

• -231 <= x <= 231 - 1

代码如下：

public int reverse(int x) {
    int max = 0x7fffffff;
    int min = 0x80000000;
    long res = 0;
    while (x != 0){
        res *= 10;
        res += x%10;
        x /=10;
    }
    if(res < min || res > max){
        return 0;
    }
    return (int)res;
}