LeetCode OJ：Divide Two Integers（两数相除）

Divide two integers without using multiplication, division and mod operator.

If it is overflow, return MAX_INT.

两数相除，不能用*,/,%  那么只能用位移运算了，注意边界条件防止溢出，代码如下：

class Solution {
public:
    int divide(int dividend, int divisor) {
        int sign1 = dividend > 0 ? 1 : -1;
        int sign2 = divisor > 0 ? 1 : -1;
        long long d1 = abs(static_cast<long long>(dividend));
        long long d2 = abs(static_cast<long long>(divisor));
        int res = 0;
        while(d1 >= d2){
            long long tmp = d2;
            for(int i = 0; d1 >= tmp; ++i){
                d1 -= tmp;
                tmp <<= 1;
                res += 1LL << i;
            }
        }
        if(sign1 == sign2){
            if(res == INT_MIN)
                return INT_MAX;
            return res;
        }else
            return res * -1;
    }
};

PS:这题溢出情况相当恶心。