《Leetcode每日一题》29.两数相除

 关键：

1.学会使用位运算

2.被除数减小，除数增大

class Solution {
public:
    int divide(int dividend, int divisor) {
        if(dividend == 0) return 0;
        if (dividend == INT_MIN && divisor == -1) {
            return INT_MAX;
        }
        int symbol = (dividend >0 && divisor<0 || dividend<0 && divisor>0) ? -1:1;
        long div = abs(dividend);
        long dis = abs(divisor);
        long  num = 0;
        while(div>=dis)
        {
            long temp=dis,mid=1;
            while(div>=(temp<<1))
            {
                mid<<=1;
                temp<<=1;
            }
            num+=mid;
            div-=temp;
        }
        return symbol == 1?num:-num;
    }
};