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surrounded matrix
With a given matrix A (size m x n) create a matrix B (size m+2 x n+2) so that the matrix A is surrounded by ones: A = [1 2 ...

2 months ago

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Flip the main diagonal of a matrix
Given a n x n matrix, M, flip its main diagonal. Example: >> M=magic(5); >> flipDiagonal(M) 9 24 1 ...

2 months ago

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Back to basics 23 - Triangular matrix
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, return a matrix with all elements above a...

2 months ago

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Back to basics 21 - Matrix replicating
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, generate an output matrix that consists o...

2 months ago

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Remove NaN ?
input -> matrix (n*m) with at least one element equal to NaN; output -> matrix(p*m), the same matrix where we deleted the enti...

2 months ago

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Spiral In
Create an m by n matrix filled with sequential integers starting from 1 and arranged in a counterclockwise spiral that hugs the ...

2 months ago

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Matrix spiral
Make a spiral in a (n*n) matrix. The spiral has to start in the top left, and has to rotate clockwise to the center. The spiral ...

2 months ago

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Create a patchwork matrix
This function will assemble a large matrix out of a number of smaller ones m1, m2, etc., according to a pattern P. If P is 3x5,...

2 months ago

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Find last non-zero in a given dimension
You are given a logical matrix *BW* _of any dimension_, and a dimension *dim*. You need to find the locations of the last non-ze...

2 months ago

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Assignment Problem
Given a matrix where row i corresponds to person i, and column j corresponds to task j and cell (i,j) corresponds to the time ta...

2 months ago

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Check if a rotated array was originally sorted
Suppose a sorted array is rotated at some pivot unknown to you. For example, |[0 1 2 4 5 6 7]| might become |[5 6 7 0 1 2 4]|. ...

2 months ago

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S-T-R-E-T-C-H I-T O-U-T
You will be given a row of numbers (x), and a single number (n). Your job is to write a script that will stretch out the row of...

2 months ago

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Look Up Mapping
Let the input is A = {[] [] [] [1] []}; B = {'A','B','C','D','E'}; Mapped Output = 'D';

2 months ago

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Find longest run
Write a function longest_run that takes as input an array of 0's and 1's and outputs the length and index of the longest consecu...

2 months ago

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Sorting integers by their digits (Level 4)
This is the next step up from <http://www.mathworks.com/matlabcentral/cody/problems/42815-sorting-integers-by-their-digits-level...

2 months ago

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Sorting integers by their digits (Level 2)
This is the next step up from <http://www.mathworks.com/matlabcentral/cody/problems/42809-sorting-integers-by-their-digits Probl...

2 months ago

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Sorting integers by their digits (Level 3)
This is the next step up from <http://www.mathworks.com/matlabcentral/cody/problems/42811-sorting-integers-by-their-digits-level...

2 months ago

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Sorting integers by their digits (Level 1)
Given a vector, v, of positive integers, return a vector, w, by sorting v in ascending order, such that primary sorting is done ...

2 months ago

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generate number in particular way
A = [1 5 2 7]; MAX = 10; generate a array Y = [1 2 2 2 2 2 3 3 4 4]; i.e. total eleme...

2 months ago

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Zero Cross
Write a function that counts the number of times n a signal x changes sign. Examples x = [1 2 -3 -4 5 6 -7 8 -9 10 11] ...

2 months ago

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Weave two matrices together to form one matrix
Take the first column from matrix a, then insert the first column from matrix b, and so on. For example: a = [1 2 3 4]; b ...

2 months ago

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Getting the indices from a matrix
Inspired by Problem 645. Getting the indices from a matrix. Given a matrix A (or a vector), return the indices (always in row...

2 months ago

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Return a list sorted by number of consecutive occurrences
Inspired by Problem 38 by Cody Team. Given a vector x, return a vector y of the values in x sorted by the number of CONSECUTIVE ...

2 months ago

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Construct an index vector from two input vectors in vectorized fashion
Create an index vector defined by two input vectors, one defining the beginnings of one or more index ranges, and the other defi...

2 months ago

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Longest run of consecutive numbers
Given a vector a, find the number(s) that is/are repeated consecutively most often. For example, if you have a = [1 2 2 2 1 ...

2 months ago

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Divisible by n, prime vs. composite divisors
In general, there are two types of divisibility checks; the first involves composite divisors and the second prime divisors, inc...

2 months ago

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Find the next prime number
Find the next prime number or numbers for given n. For example: n = 1; out = 2; or n = [5 7]; out = [7 11]; ...

2 months ago

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Largest Twin Primes
<http://en.wikipedia.org/wiki/Twin_prime Twin primes> are primes p1, p2 = p1 + 2 such that both p1 and p2 are prime numbers. Giv...

2 months ago

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Mersenne Primes
A Mersenne prime is a prime number of the form M = 2^p - 1, where p is another prime number. For example, 31 is a Mersenne prim...

2 months ago

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Find nearest prime number less than input number
Find nearest prime number less than input number. For example: if the input number is 125, then the nearest prime number whi...

2 months ago