Divide Two Integers

注意的几点

1.int 类型溢出问题

2.正负数问题

class Solution {public:    int divide(int dividend, int divisor) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        long long ret=0,tmp=0,num=1;        bool sign=true;        if(dividend>0&&divisor<0||dividend<0&&divisor>0)            sign=false;        long long x=dividend,y=divisor;        x=abs(x);y=abs(y);        while(x>=y){            num=y;            tmp=1;            while(x>=num){                num=(num<<1);                tmp=tmp<<1;            }            num=num>>1;            tmp=tmp>>1;              x-=num;            ret+=tmp;        }        return sign?ret:-ret;    }};