LC 7. 整数反转

代码 :

class Solution {
public:
    int reverse(int x) {
        int res = 0; 
        while(x != 0) {
            // res * 10 + x % 10 > INT_MAX
            if(res > 0 && res > (INT_MAX - x % 10) / 10)
                return 0;
            // res * 10 + x % 10 < INT_MIN
            if(res < 0 && res < (INT_MIN - x % 10) / 10)
                return 0;
            res = res * 10 + x % 10;
            x /= 10;
        }
        return res;
    }
};
/*
123
(((0 * 10 + 3) * 10) + 2) * 10 + 1 
*/

class Solution {
public:
    int reverse(int x) {
        bool sign = x > 0 ? true : false;
        string s = to_string(x);
        std::reverse(s.begin(), s.end());
        int res = 0;
        try {
            res = stoi(s);
        }
        catch (std::out_of_range&){
           return 0;
        }
        if(!sign) return -1 * res;
        return res;
    }
};