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。