7. Reverse Integer

Reverse digits of an integer.

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

题意：翻转数字，细节：溢出输出0，10，100，1000等等输出1

class Solution {public:    int reverse(int x) {        int sym = 1;        long long int y = x;        if(y < 0){            sym = -1;            y = -y;        }        vector<int> tmp;        while(y != 0){            tmp.push_back(y % 10);            y /= 10;        }        long long int rev = 0;        int sz = tmp.size();        for(int i = 0; i < sz; ++i){            rev = rev * 10 + tmp[i];        }        if((sym == 1 && rev > 2147483647) || (sym == -1 && rev > 2147483648)) return 0;        return rev * sym;    }};