将两个整数相除，要求不使用乘法、除法和 mod 运算符。如果溢出，返回 2147483647 。

class Solution {public:    int divide(int dividend, int divisor) {        // Write your code here        const int OVER_FLOW = 2147483647;                 long long divd = dividend;        long long divr = divisor;                if (divr == 0) {            return OVER_FLOW;        }        int flag = 1;        if (divd < 0 && divr > 0  || divd > 0 && divr < 0) {            flag = -1;        }

divd  = abs(divd);        divr = abs(divr);                long long ret = 0;                while (divr <= divd) {            long long cnt = 1;            long long tmp = divr;            while (tmp <= divd) {                divd -= tmp;                ret += cnt;                cnt <<= 1;                tmp <<= 1;            }        }                ret *= flag;                 if (ret > INT_MAX || ret < INT_MIN) {            return OVER_FLOW;        }        return ret;    }    };