19.1.20 [LeetCode 7]Reverse Integer

Easy

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) {
        long long y = 0;
        while (x) {
            y *= 10;
            y += x % 10;
            x /= 10;
        }
        if (y > INT_MAX || y < INT_MIN)return 0;
        return y;
    }
};

简单翻转……只是要注意溢出情况