Problem 810. Hamming Weight - Size Scoring

The Hamming Weight, wiki Hamming Weight, in its most simple form is the number of ones in the binary representation of a value.

The task here is to create a fast Hamming Weight function/method such that processing many 4K x 4K images of 32 bit integer can be evaluated rapidly. Saw this question posed on Stack Overflow.

Input: Vector of length N of 32 bit integer values.

Output: Total number of ones of the binary representation

Scoring: Normal Cody Size, while solving multiple cases without timing out

Examples: Input [7 ; 3], output=[3 ; 2]; [16 32], output [1 ; 1]; [0 4294967295] output [ 0 ; 32] FFFFFFFF Hex = 2^32-1

Stressing Test vector : uint32(randi(2^32,[4096*4096,1])-1)

Helpful, possibly, global variables.

b1=uint32(1431655765); b2=uint32(858993459); b3=uint32(252645135) b4=uint32(16711935); b5=uint32(65535);

Hex: b1=55555555 b2=33333333 b3=0F0F0F0F b4=00FF00FF b5=0000FFFF

The array num_ones is created for values 0-65535 (0:2^16-1). num_ones(1)=0, num_ones(2)=1, num_ones(3)=1,num_ones(4)=2,...num_ones(65536)=15

Due to lack of zero indexing num_ones(value+1) is number of ones for value.

Solution Stats

23.91% Correct | 76.09% Incorrect
Last Solution submitted on Jun 02, 2023

Problem Comments

Solution Comments

Show comments

Problem Recent Solvers10

Suggested Problems

More from this Author295

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!