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Triangle Numbers
Triangle numbers are the sums of successive integers. So 6 is a triangle number because 6 = 1 + 2 + 3 which can be displa...

7 years ago

Solved

Find the nearest prime number
Happy 5th birthday, Cody! Since 5 is a prime number, let's have some fun looking for other prime numbers. Given a positive in...

7 years ago

Solved

The 5th Root
Write a function to find the 5th root of a number. It sounds easy, but the typical functions are not allowed (see the test su...

7 years ago

Solved

Determine if input is odd
Given the input n, return true if n is odd or false if n is even.

7 years ago

Solved

Pentagonal Numbers
Your function will receive a lower and upper bound. It should return all pentagonal numbers within that inclusive range in ascen...

7 years ago

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Pernicious Anniversary Problem
Since Cody is 5 years old, it's pernicious. <http://rosettacode.org/wiki/Pernicious_numbers Pernicious number> is an integer whi...

7 years ago

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Energy of a photon
Given the frequency F of a photon in giga hertz. Find energy E of this photon in giga electron volts. Assume h, Planck's ...

7 years ago

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How to subtract?
* Imagine you need to subtract one number from another using MATLAB. * You will not be using eval for this task. * Given two A...

7 years ago

Solved

Shift elements of vector left
Shift elements of vector to the left. For ex. : Input_vec = [1 2 3 4 5] Output_vec = [2 3 4 5 1]

7 years ago

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Average of even-numbered columns
Given a vector, find the average of even-numbered columns. e.g x　=　[ 4 6 8 9 1 2 7 ] y =　( 6 + 9 + 2 ) / 3

7 years ago

Solved

Return the 3n+1 sequence for n
A Collatz sequence is the sequence where, for a given number n, the next number in the sequence is either n/2 if the number is e...

10 years ago

Solved

Find max
Find the maximum value of a given vector or matrix.

11 years ago

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sum of non-primes
The sum of the non-primes below 10 is 1+4+6+8+9+10=38 Find the sum of all the non-primes below the input, N.

11 years ago

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Which values occur exactly three times?
Return a list of all values (sorted smallest to largest) that appear exactly three times in the input vector x. So if x = [1 2...

12 years ago

Solved

Find all elements less than 0 or greater than 10 and replace them with NaN
Given an input vector x, find all elements of x less than 0 or greater than 10 and replace them with NaN. Example: Input ...

12 years ago

Solved

Generate N equally spaced intervals between -L and L
Given N and L, return a list of numbers (in ascending order) that divides the interval [-L L] into N equal-length segments. F...

12 years ago

Solved

"mirror" matrix
Create n x 2n "mirror" matrix of this type: e.g. for n = 2 m = [1 2 2 1;1 2 2 1] e.g. for n = 3 m = [1 2 3 3 2 1...

12 years ago

Solved

Find the numeric mean of the prime numbers in a matrix.
There will always be at least one prime in the matrix. Example: Input in = [ 8 3 5 9 ] Output out is 4...

12 years ago

Solved

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...

12 years ago

Solved

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)...

12 years ago

Solved

Duplicate each element of a vector.
for an n-dimensional vector x, the function should return another vector 2n-dimension which each element is repeated twice. Ex...

12 years ago

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Determine Whether an array is empty
Input a matrix x, output y is TRUE if x is empty, otherwise FALSE.

12 years ago

Solved

Convert a vector into a number
This is a sub problem related to this problem: <http://www.mathworks.com/matlabcentral/cody/problems/621-cryptomath-addition>...

12 years ago

Solved

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 ...

12 years ago

Solved

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...

12 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...

12 years ago

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Back to basics 8 - Matrix Diagonals
Covering some basic topics I haven't seen elsewhere on Cody. Given an input vector of numbers, output a square array with the...

12 years ago

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Back to basics 6 - Column Vector
Covering some basic topics I haven't seen elsewhere on Cody. Given an input vector, output true or false whether it is a colu...

12 years ago

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Find the sum of the elements in the "second" diagonal
Find the sum of the elements in the diagonal that starts at the top-right corner and ends at the bottom-left corner.

12 years ago

Solved

radius of a spherical planet
you just measured its surface area, that is the input.

12 years ago