计数在比特数 [英] Count bits in the number

问题描述

<一个href=\"http://stackoverflow.com/questions/109023/best-algorithm-to-count-the-number-of-set-bits-in-a-32-bit-integer\">Best算法来计算一个32位整数设置的位数？

---

假设你有一个数字。有没有什么方法来计算相等于1这个数字，不使用迭代的二进制重新presentation位？我的意思是，有没有办法使用一些位运算符和口罩，以做到在固定的时间。我需要的解决方案，将两种架构的32位和64位工作。啊差点忘了，我需要它的C语言或汇编语言也是不错的。

Suppose you have a number. Is there any way to count the bits which equals to 1 in binary representation of that number, not using iteration? I mean, is there any way to do it in constant time using some bitwise operators and masks. I need solution which will work well for both architectures 32 bit and 64 bit. Ah almost forgot, I need it for C language or assembler is also good.

推荐答案

有一个位处的 http://graphics.stanford.edu/~seander/bithacks.html 。位计数算法在很多的http：// gurmeetsingh.word press.com / 2008/08/05 /快位计数例程/

There is a bit counting algorithm without a loop at http://graphics.stanford.edu/~seander/bithacks.html. Lots of bit counting algorithms at http://gurmeetsingh.wordpress.com/2008/08/05/fast-bit-counting-routines/

这篇关于计数在比特数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！