divide-two-integers

【题目描述】Divide two integers without using multiplication, division and mod operator.
不使用乘，除，模符号作除法运算

【解题思路】每一个数都可以用2进制表示，利用这一点通过位运算完成

【考查内容】模拟

class Solution {
public:
    int divide(int dividend, int divisor) {
        long long a = abs((long long)dividend); 
        long long b = abs((long long)divisor); 
        int finalcount=0;
        while(a >= b){
           int count = 1;
  
            long sum = b;
            while(sum + sum <= a){
                sum += sum;
                count += count;
            }
            a -= sum;
            finalcount += count;
        };
          
        return (dividend>>31 ^ divisor>>31)? -finalcount:finalcount; 
    }
};