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Matrix with different incremental runs
Given a vector of positive integers a = [ 3 2 4 ]; create the matrix where the *i* th column contains the vector *1:a(i)...

2 years ago

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Rotate input square matrix 90 degrees CCW without rot90
Rotate input matrix (which will be square) 90 degrees counter-clockwise without using rot90,flipud,fliplr, or flipdim (or eval)....

2 years 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 years ago

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Set some matrix elements to zero
First get the maximum of each *row*, and afterwards set all the other elements to zero. For example, this matrix: 1 2 3 ...

2 years ago

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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 years ago

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Make an awesome ramp for a tiny motorcycle stuntman
Okay, given a vector, say v=[1 3 6 9 11], turn it into a matrix 'ramp' like so: m=[1 3 6 9 11; 3 6 9 11 0; 6 9 ...

2 years 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 years 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 years 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 years 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 years ago

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Sophie Germain prime
In number theory, a prime number p is a *Sophie Germain prime* if 2p + 1 is also prime. For example, 23 is a Sophie Germain prim...

2 years ago

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Reverse the elements of an array
Reverse the order of elements in an array: eg: input X = [ 1 2 3 ; 4 5 6 ; 7 8 9 ] o...

2 years 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 years 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 years 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 years ago

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The Goldbach Conjecture
The <http://en.wikipedia.org/wiki/Goldbach's_conjecture Goldbach conjecture> asserts that every even integer greater than 2 can ...

2 years ago

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Fibonacci Decomposition
Every positive integer has a unique decomposition into nonconsecutive Fibonacci numbers f1+f2+ ... Given a positive integer n, r...

2 years ago

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Too Many Zeros, Dump Them!
Sometimes when I create a matrix, I use this syntax: a = zeros(1000,1000); But when the function ends, I find that I don'...

2 years ago

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How many Fibonacci numbers?
Find the number of unique Fibonacci numbers (don't count repeats) in a vector of positive integers. Example: x = [1 2 3 4...

2 years ago

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Number of Even Elements in Fibonacci Sequence
Find how many even Fibonacci numbers are available in the first d numbers. Consider the following first 14 numbers 1 1 2...

2 years ago

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Enlarge array
Given an m-by-n numeric array (A) and a 1-by-2 vector (sz) indicating the dimensions [p q] to enlarge each element, return an (m...

2 years ago

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subtract central cross
Given an n-by-n square matrix, where n is an odd number, return the matrix without the central row and the central column.

2 years ago

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Remove entire row and column in the matrix containing the input values
Remove the entire row and column from the matrix containing specific values. The specified value can be a scalar or a vector. Fo...

2 years ago

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frame of the matrix
Given the matrix M, return M without the external frame.

2 years ago

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Replace Nonzero Numbers with 1
Given the matrix x, return the matrix y with non zero elements replaced with 1. Example: Input x = [ 1 2 0 0 0 ...

2 years ago

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Write a function man that takes a row vector v and returns a matrix H as follows..
Write a function called man that takes a row vector v as an input and returns a matrix H whose first column consist of the eleme...

2 years ago

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A matrix of extroverts
Now that the introverts have had their script, the extroverts spoke up (naturally!) and demanded one as well. You will be given...

2 years ago

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Matrix multiplication across rows
Given matrix m, return matrix n such that, rows of n are result of multiplication of the rows of the input matrix Example ...

2 years ago

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Finding Perfect Squares
Given a vector of numbers, return true if one of the numbers is a square of one of the numbers. Otherwise return false. Example...

2 years ago

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Make a vector of prime numbers
Input(n) - length of vector with prime numbers Output(v) - vector of prime numbers Example: * n=1; v=2 * n=3; v=[2 3 5...

2 years ago