29. Divide Two Integers

最新推荐文章于 2022-05-31 11:11:52 发布

转载最新推荐文章于 2022-05-31 11:11:52 发布 · 48 阅读

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原文链接：http://www.cnblogs.com/goPanama/p/9607783.html

本文介绍了一种在Java中实现整数除法的高效算法，通过将被除数和除数转换为正数和long类型，使用二进制搜索思想进行除法运算，避免了传统的逐位相减方法，提高了运算速度。

 1 class Solution {
 2     public int divide(int dividend, int divisor) {
 3         long count = 0;
 4         if(dividend == 0) return 0;
 5         //divisor和dividend都要变成正数和long再进行处理
 6         if((dividend > 0 && divisor >0) || (dividend < 0 && divisor < 0)) {
 7              long ldivisor = Math.abs((long)divisor);
 8              long ldividend = Math.abs((long)dividend);
 9              count = longdivide(ldividend, ldivisor);
10             
11         }else {
12             long ldivisor = Math.abs((long)divisor);
13             long ldividend = Math.abs((long)dividend);
14             count = -longdivide(ldividend, ldivisor);
15             }
16             
17         //overflow处理
18         if(count > 0) {
19             return (int) (count > Integer.MAX_VALUE ? Integer.MAX_VALUE : count);
20         }else {
21             return (int) (count < Integer.MIN_VALUE ? Integer.MIN_VALUE : count);
22         }
23         
24         
25     }
26     
27     //类似binary search
28     public long longdivide(long dividend, long divisor) {
29         if(dividend < divisor) return 0;
30         long multiple = 1;
31         long sum = divisor;
32         while((sum + sum) < dividend) {
33             sum += sum;
34             multiple +=multiple;
35         }
36         return multiple + longdivide(dividend - sum, divisor);
37         
38     }
39 }