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Add Me To Death (Sum sum sum)
Given certain vector, sum of the input vector, get the sum of 2 adjacent numbers in the input, and sum of the output vector (wh...

3 years ago

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Get all prime factors
List the prime factors for the input number, in decreasing order. List each factor. If the prime factor occurs twice, list it as...

3 years ago

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Sum the Digits of a Number
Given an integer, sum the digits repeatedly until you end up with a single value less than 10. For example, if you add the di...

3 years ago

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Replace values out of an interval with the lower or upper values
For a vector or matrix X and an interval [n1,n2], the function replace every element of x inferior to n1 by n1, and every elemen...

3 years ago

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Number construction III
Given a positive integer, n, return a, b and c, such that 1. n = a^1.5+b^2.5+c^3.5 2. a, b and c are all positive integers...

3 years ago

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Number construction II
Given a positive integer, n, return a, b, c and d, such that 1. n = a*2^b+c*3^d 2. a, b, c and d are all positive integers...

3 years ago

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Number construction I
Given a positive integer, n, return a, b, c and d, such that 1. n = a*sqrt(b)+c*sqrt(d) 2. a, b, c and d are all positive ...

3 years ago

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Evened up (or not)
You will be provided with an array or matrix that contains various numbers, in addition to an evening variable, e, set to 1 or 0...

3 years ago

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De-primed
Write a function that will multiply every prime number in the array or matrix by two, leaving all other numbers the same, and re...

3 years ago

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How many trades represent all the profit?
Given a list of results from trades made: [1 3 -4 2 -1 2 3] We can add them up to see this series of trades made a profit ...

3 years ago

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Find a subset that divides the vector into equal halves
Given a vector x, return the indices to elements that will sum to exactly half of the sum of all elements. Example: Inpu...

3 years ago

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How long is the longest prime diagonal?
Stanislaw Ulam once observed that if the counting numbers are arranged in a spiral, the prime numbers contained in it form a sur...

3 years ago

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Flag largest magnitude swings as they occur
You have a phenomenon that produces strictly positive or negative results. delta = [1 -3 4 2 -1 6 -2 -7]; Marching through thi...

3 years ago

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Make a run-length companion vector
Given a vector x, return a vector r that indicates the run length of any value in x. Each element in r shows how many times the ...

3 years ago

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Implement simple rotation cypher
If given a letter from the set: [abc...xyz] and a shift, implement a shift cypher. Example: 'abc' with a shi...

3 years ago

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"Look and say" sequence
What's the next number in this sequence? * [0] * [1 0] * [1 1 1 0] * [3 1 1 0] * [1 3 2 1 1 0] This a variant on the w...

3 years ago

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Van Eck's Sequence's nth member
Return the Van Eck's Sequence's nth member. For detailed info : <http://oeis.org/A181391 OEIS link> and <https://www.theguard...

3 years ago

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5 Prime Numbers
Your function will be given lower and upper integer bounds. Your task is to return a vector containing the first five prime numb...

3 years ago

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Extra safe primes
Did you know that the number 5 is the first safe prime? A safe prime is a prime number that can be expressed as 2p+1, where p is...

3 years ago

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Alternating sum
Given vector x, calculate the alternating sum y = x(1) - x(2) + x(3) - x(4) + ...

3 years ago

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Integer sequence - 2 : Kolakoski sequence
Get the n-th term of Kolakoski Sequence.

3 years ago

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Read a column of numbers and interpolate missing data
Given an input cell array of strings s, pick out the second column and turn it into a row vector of data. Missing data will be i...

3 years ago

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Interpolator
You have a two vectors, a and b. They are monotonic and the same length. Given a value, va, where va is between a(1) and a(end),...

3 years ago

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Kaprekar Steps
6174 is the <http://en.wikipedia.org/wiki/6174_%28number%29 Kaprekar constant>. All natural numbers less than 10,000 (except som...

3 years ago

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Find x rows where the sum of the numbers is the maximum
Find x rows where the sum of the numbers is the maximum. For example: when x is 2 and m is 2 3 5 0 2 3 5 5 6 0 9 4 then y =...

3 years ago

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Draw a '1' in a zero matrix!

3 years ago

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Target sorting
Sort the given list of numbers |a| according to how far away each element is from the target value |t|. The result should return...

3 years ago

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Replace NaNs with the number that appears to its left in the row.
Replace NaNs with the number that appears to its left in the row. If there are more than one consecutive NaNs, they should all ...

3 years ago

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Return the largest number that is adjacent to a zero
This example comes from Steve Eddins' blog: <http://blogs.mathworks.com/steve/2009/05/27/learning-lessons-from-a-one-liner/ Lear...

3 years ago

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Duplicates
Write a function that accepts a cell array of strings and returns another cell array of strings *with only the duplicates* retai...

3 years ago