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

 1 public class Solution {
 2     public int divide(int dividend, int divisor) {
 3         if(0 == dividend || 0 == divisor)
 4             return 0;
 5         boolean isNeg = ((dividend > 0 && divisor < 0) || (dividend < 0 && divisor > 0)) ? true : false;
 6         long dividen_long = Math.abs((long)dividend);
 7         long divisor_long = Math.abs((long)divisor);
 8         if(divisor_long > dividen_long)
 9             return 0;
10         
11         long sum = 0;
12         long pow = 0;
13         long result = 0;
14         
15         while(divisor_long <= dividen_long){
16             sum = divisor_long;
17             pow = 1;
18             while(sum + sum <= dividen_long){
19                 sum += sum;
20                 pow += pow;
21             }//while
22             dividen_long -= sum;
23             result += pow;
24         }//while
25         
26         result = isNeg ?  -result : result;
27         if(result > Integer.MAX_VALUE || result < Integer.MIN_VALUE)
28             return Integer.MAX_VALUE;
29         
30         return (int)result;
31     }
32 }