Divide Two Integers

参考：http://www.cnblogs.com/springfor/p/3871008.html

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

If it is overflow, return MAX_INT.

这道看了网上的很多都是通过移位来做的，硬是没看懂

看了一下这个锅锅的，终于懂了

public class Solution {
    public int divide(int dividend, int divisor) {
        if(0 == dividend || 0 == divisor)
            return 0;
        boolean isNeg = ((dividend > 0 && divisor < 0) || (dividend < 0 && divisor > 0)) ? true : false;
        long dividen_long = Math.abs((long)dividend);
        long divisor_long = Math.abs((long)divisor);
        if(divisor_long > dividen_long)
            return 0;
        
        long sum = 0;
        long pow = 0;
        long result = 0;
        
        while(divisor_long <= dividen_long){
            sum = divisor_long;
            pow = 1;
            while(sum + sum <= dividen_long){
                sum += sum;
                pow += pow;
            }//while
            dividen_long -= sum;
            result += pow;
        }//while
        
        result = isNeg ?  -result : result;
        if(result > Integer.MAX_VALUE || result < Integer.MIN_VALUE)
            return Integer.MAX_VALUE;
        
        return (int)result;
    }
}