leetcode 7. Reverse Integer

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.

 

class Solution {
public:
    int reverse(int x) {
        int rev = 0;
        while (x != 0) {
            int pop = x % 10;
            x /= 10;
            if (rev > INT_MAX / 10 || (rev == INT_MAX / 10 && pop > INT_MAX % 10))
                return 0;
            if (rev < INT_MIN / 10 || (rev == INT_MIN / 10 && pop < INT_MIN % 10))
                return 0;
            rev = rev * 10 + pop;
        }
        return rev;
    }
};