LeetCode7. Reverse Integer

Posted 2020-08-08 医生工程师

题目

Reverse digits of an integer.

Example1: x = 123, return 321
Example2: x = -123, return -321

简单题，需要考虑两个问题，1）如果输入的末尾是0怎么办？2）如果倒过来的数字溢出了怎么办？

class Solution {
public:
    int reverse(int x) {
        int flag = 1;
        unsigned res = 0;;
        if (x < 0){
            flag = -1;
            x = flag * x;
        }
        
        while (x > 0)
        {
            if (res > (INT_MAX - x%10)/10)
                    return 0;
            res = res*10 + x%10;
            x = x/10;
        }
        
        return flag * (int)res;
    }
};