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Mersenne Primes vs. All Primes
A Mersenne prime (M) is a prime number of the form M = 2^p - 1, where p is another prime number. <https://www.mathworks.com/matl...

1 year ago

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The Goldbach Conjecture
The Goldbach conjecture asserts that every even integer greater than 2 can be expressed as the sum of two primes. Given the eve...

1 year ago

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Divisors for big integer
Inspired by Problem 1025 and Project Euler 12. Given n, return the number y of integers that divide N. For example, with ...

1 year ago

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Sum of big primes without primes
Inspired by Project Euler n°10 (I am quite obviously a fan). With problem n°250 by Doug, you can find some global methods to co...

1 year ago

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First non-zero element in each column
For a given matrix, calculate the index of the first non-zero element in each column. Assuming a column with all elements zero i...

1 year ago

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Determine the number of odd integers in a vector
Determine the number of unique odd integers in a vector. Examples: Input x = [2 5 8 3 7 1]; Output y = 4; Inp...

1 year ago

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Max index of 3D array
Given a three dimensional array M(m,n,p) write a code that finds the three coordinates x,y,z of the Maximum value. Example ...

1 year ago

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Finding peaks
Find the peak values in the signal. The peak value is defined as the local maxima. For example, x= [1 12 3 2 7 0 3 1 19 7]; ...

1 year ago

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Change the sign of even index entries of the reversed vector
change the signs of the even index entries of the reversed vector example 1 vec = [4 -1 -2 9] ans = [9 2 -1 -4] example2...

1 year ago

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Insert zeros into vector
Insert zeros after each elements in the vector. Number of zeros is specified as the input parameter. For example: x = [1 ...

1 year ago

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Create a vector whose elements depend on the previous element
The idea is to create a vector A whose elements depend on the previous element : *A(i+1) = 2*A(i)+1* *2 Inputs*: - A : The...

1 year ago

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Create an n-by-n null matrix and fill with ones certain positions
The positions will be indicated by a z-by-2 matrix. Each row in this z-by-2 matrix will have the row and column in which a 1 has...

1 year ago

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Unique values without using UNIQUE function
You must return unique values in a vector in *stable* mode without using the unique function. About stable order flag: ...

1 year ago

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Find nth maximum
Find nth maximum in a vector of integer numbers. Return NaN if no such number exists. x = [2 6 4 9 -10 3 1 5 -10]; So ...

1 year ago

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Create an index-powered vector
Given a input vector x, return y as index-powered vector as shown below. Example x = [2 3 6 9] then y should be [...

1 year ago

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Oh Zero Zero Zero!!!
Hello all, So you have to find the largest section of zeros in a vector and then find the length of those zeros and there start...

1 year ago

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Find last zero for each column
Given a numeric array of arbitrary size, return the row index of the last zero for each column. If a column contains all nonzero...

1 year ago

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Count consecutive 0's in between values of 1
So you have some vector that contains 1's and 0's, and the goal is to return a vector that gives the number of 0's between each ...

1 year ago

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Calculate the Number of Sign Changes in a Row Vector (No Element Is Zero)
For a row vector: V=[7 1 2 -3] there is one sign change (from 2 to -3). So, the function you write must return N=1. F...

1 year ago

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String Logic 19
Examples: 'DIG' --> 'I' 'IMPORTANT' --> 'MOTN' 'DEAL' --> 'EL' 'LIMB' --> 'IB' 'MOSTLY' --> 'OTY'

1 year 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...

1 year 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...

1 year ago

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Symmetry of vector
Determine whether the vector is symmetric or not (vector could be even or odd in length). For example: x = [1 2 3 3 2 1] is s...

1 year ago

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Set the array elements whose value is 13 to 0
Input A either an array or a vector (which can be empty) Output B will be the same size as A . All elements of A equal to 13...

1 year 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...

1 year ago

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sum of non-primes
The sum of the non-primes no larger than 10 is 1+4+6+8+9+10=38 Find the sum of all the positive non-prime integers that do no...

1 year 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.

1 year ago

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Nilpotent matrix
Check if matrix A is <http://mathworks.com/ nilpotent>.

1 year 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 ...

1 year ago

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Spherical Volume
Calculate the volume of a sphere.

1 year ago