Divide Two Integers

class Solution {
public:
    int divide(int dividend, int divisor) {
        
         if (dividend == INT_MIN && divisor == -1)
            return INT_MAX;
         if (dividend == 0 || divisor == 0)
            return 0;

        int nega = 0;
        if ((dividend>0&&divisor<0) || (dividend<0&&divisor>0))
            nega = 1;
        long long d=dividend;//int数据abs(-2147483648)会溢出，因为正数int只能到2147483647,所以需要long long 来存储一下
        long long s=divisor;
        long long den = abs(d);
        long long sor = abs(s);
        if (sor > den)
            return 0;
        long long sum = 0;
        int count = 0;
        int res = 0;
        while (den >= sor)
        {
            count = 1;                //a >= b保证了最少有一个count
            sum = sor;
            while (sum + sum <= den){    //!!
                sum += sum;
                count += count;
            }
            den -= sum;
            res += count;
        }

        if (nega)
            res = 0 - res;
        return res;
    }
};