Hamming Weight的算法分析(转载)】的更多相关文章

看代码时遇到一个求32bit二进制数中1的个数的问题,感觉算法很奇妙,特记录学习心得于此,备忘. 计算一个64bit二进制数中1的个数. 解决这个问题的算法不难,很自然就可以想到,但是要给出问题的最优解,却很有难度. 通常,最容易想到的算法是除余法,继而考虑到除法的代价较高,而且除数是2,会想到使用向右移位来代替除法,并使用&0x1操作来取末位的值,这样提高了算法的效率.然而,这样仍然进行了63次&操作.63次移位操作和63次+操作.若假设字长大小不限,记作N,那么上述算法的时间复杂度都为…
1.问题来源 之所以来记录这个问题的解法,是因为在在线编程中经常遇到,比如编程之美和京东的校招笔试以及很多其他公司都累此不疲的出这个考题.看似简单的问题,背后却隐藏着很多精妙的解法.查找网上资料,才知道这个问题的正式的名字叫Hamming weight(汉明重量). 2.问题描述 对于一个无符号整型数,求其二进制表示中1的个数.比如12的以32位无符号整型来表示,其二进制为:00000000 00000000 00000000 00001100,那么12的二进制中1的个数是两个. 3.具体解法…
variable-precision SWAR算法:计算Hamming Weight 转自我的Github 最近看书看到了一个计算Hamming Weight的算法,觉得挺巧妙的,纪录一下. Hamming Weight,即汉明重量,指的是一个位数组中非0二进制位的数量. 对于这个问题,最直观的算法就是遍历二进制位,时间复杂度是O(n),每次需要遍历n个位.另外一个算法是查表,用一个数组记录下一定位数每个数值的汉明重量如:数组hwTable=[0, 1, 1, 2]纪录了0, 1, 2, 3的汉…
仔细阅读ORB的代码,发现有很多细节不是很明白,其中就有用暴力方式测试Keypoints的距离,用的是HammingLUT,上网查了才知道,hamming距离是相差位数.这样就好理解了. 我理解的HammingLUT lut; result=lut((a),(b),size_t size):result=a与b的hamming distance+size; unsigned int hamdist(unsigned int x, unsigned int y) { unsigned int di…
------------------------------------------- 本文系作者原创, 欢迎大家转载! 转载请注明出处:netwalker.blog.chinaunix.net ------------------------------------------- 通过位图提供的两种状态可以在非常节约内存的情况下表示开关变量,并且同类这类变量可以紧凑而高效的统一进行处理.有很多内核子系统都需要位图的支持,但是不同的情况又需要不同的位图个数,比如SMP系统上的CPU位图cpuma…
本文是在学习中的总结.欢迎转载但请注明出处:http://blog.csdn.net/pistolove/article/details/44486547 Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the Hamming weight). For example, the 32-bit integer '11' has binar…
Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the Hamming weight). For example, the 32-bit integer '11' has binary representation 00000000000000000000000000001011, so the function should retu…
一天一道LeetCode 本系列文章已全部上传至我的github,地址:ZeeCoder's Github 欢迎大家关注我的新浪微博,我的新浪微博 欢迎转载,转载请注明出处 (一)题目 Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the Hamming weight). For example, the 32-bit integer…
---不包含jiuzhang ladders中出现过的题.如出现多个方法,则最后一个方法是最优解. 目录: 1 String 2 Two pointers 3 Array 4 DFS && BFS 5 Math 6 Dynamic Programming 7 Data Structure 8 Binary Search 9 Tree 10 Bit Manipulation 11 Linked List 12 graph 1 String 1.1  Longest Palindromic S…
最近在菜鸟教程上自学redis.看到Redis HyperLogLog的时候,对"基数"以及其它一些没接触过(或者是忘了)的东西产生了好奇. 于是就去搜了"HyperLogLog",从而引出了Cardinality Estimation算法,以及学习它时参考的一些文章: http://blog.codinglabs.org/articles/algorithms-for-cardinality-estimation-part-i.html 从文章上看来,基数是指一个…
Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the function should retu…
题目描述: Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the Hamming weight). For example, the 32-bit integer '11' has binary representation 00000000000000000000000000001011, so the function shoul…
按位操作符只能用于整数基本数据类型中的单个bit中,操作符对应表格: Operator Description & 按位与(12345&1=1,可用于判断整数的奇偶性) | 按位或 ^ 异或(同假异真) ~ 非(一元操作符) &=,|=,^= 合并运算和赋值 <<N 左移N位,低位补0 >>N 右移N位,(正数:高位补0,负数高位补1) >>>N 无符号右移(无论正负数,高位皆补0) <<=,>>=,>>…
题目: Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the function should…
191. Number of 1 Bits Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so th…
英文出自:Streamcomputing 转自:http://www.csdn.net/article/2013-10-29/2817319-the-application-areas-opencl-can-be-used 摘要:个经典案例.有人将其称之为OpenCL计算领域的13个"小巨人". 一.Dense Linear Algebra(稠密线性代数) 级(矢量/矢量vector/vector),2级(矩阵/矢量),3级(矩阵/矩阵),应用范围极其广泛. 应用范围: 线性代数:LA…
Problem: Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the Hamming weight). For example, the 32-bit integer '11' has binary representation 00000000000000000000000000001011, so the function sh…
1.有可能是类的函数实现的时候错误. 如:应该为MVT_PAR1* GpsTcpCallback::GetMUT_PAR1(unsigned char* data,int i), 却写成了MVT_PAR1* GetMUT_PAR1(unsigned char* data,int i) 错误提示:error LNK2001: unresolved external symbol public: struct MVT_PAR1 * __thiscall GpsTcpCallback::GetMUT_…
原题链接在这里:https://leetcode.com/problems/number-of-1-bits/ 题目: Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11' has binary representation 0…
一:Number of 1 Bits 题目: Write a function that takes an unsigned integer and returns the number of '1' bits it has (also known as the Hamming weight). For example, the 32-bit integer '11' has binary representation 00000000000000000000000000001011, so t…
Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the function should retu…
Number of 1 Bits Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the fun…
eclipse没问题,leetcode 1不能通过,超出int最大值了,但是怎么转无符号? /*Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11' has binary representation 0000000000000…
通过位图提供的两种状态可以在非常节约内存的情况下表示开关变量,并且同类这类变量可以紧凑而高效的统一进行处理.有很多内核子系统都需要位图的支持,但是不同的情况又需要不同的位图个数,比如SMP系统上的CPU位图cpumask的位数位NR_CPUS,而内存管理区的位图数为MAX_ZONES_PER_ZONELIST.但是所有的位图都要转换为基本的数据类型,比如int,short等,Linux将定义位图的功能集中到一个名为DECLARE_BITMAP的宏. include/linux/types.h #…
https://en.wikipedia.org/wiki/RSA_(cryptosystem) RSA is one of the first practical实用性的 public-key cryptosystems and is widely used for secure data transmission. In such a cryptosystem密码系统, the encryption key is public and differs from the decryption…
Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the function should retu…
190 - Reverse Bits Reverse bits of a given 32 bits unsigned integer. For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 (represented in binary as00111001011110000010100101000000). Follow up…
https://www.hackerrank.com/contests/w6/challenges/acm-icpc-team 这道题在contest的时候数据量改小过,原来的数据量需要进行优化才能过.参考了:http://chasethered.com/2014/07/hackerrank-weekly-challenge-6-problem-1/ 首先是转化成int32的数组,然后N^N的复杂度两两比较求bit数.求bit中1的个数有几种做法: - x & (x - 1)- Hamming…
题目描述: Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the function shoul…
题目: Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the function should…