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How long is the longest prime diagonal?

Stanislaw Ulam once observed that if the counting numbers are <http://en.wikipedia.org/wiki/Ulam_spiral arranged in a spiral>, t...

5 months ago

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Solitaire Cipher

Implement the <http://en.wikipedia.org/wiki/Solitaire_(cipher) solitaire cipher>. Since this is from Wikipedia, I am capturin...

5 months 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...

5 months ago

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Spot the outlier

All points except for one lie on a line. Which one is the outlier? Example: You are given a list of x-y pairs in a column ...

5 months 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 ...

5 months 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 thr...

5 months ago

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Find the biggest empty box

You are given a matrix that contains only ones and zeros. Think of the ones as columns in an otherwise empty floor plan. You wan...

5 months ago

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Great Circle Distance

Find shortest between two points on a ball given their azimuthal and polar angles (in degrees) as well as the radius of the sphe...

5 months ago

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Smallest distance between a point and a rectangle

Given two points *x* and *y* placed at opposite corners of a rectangle, find the minimal euclidean distance between another poin...

5 months ago

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Clockwise or Counterclockwise

Given a list of 2-d points defining the vertices of a polygon, determine whether these points are sorted clockwise. The input...

5 months ago

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Numbers with prime factors 2, 3 and 5.

Make a function which takes one positive integer n and returns a matrix with the numbers of the form (2^i)*(3^j)*(5^k) which are...

5 months ago

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Proper Factors

Generate the proper factors of input integer _x_ and return them in ascending order. For more information on proper factors, ref...

5 months ago

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Circular Primes (based on Project Euler, problem 35)

The number, 197, is called a circular prime because all rotations of the digits: 197, 971, and 719, are themselves prime. The...

5 months 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 ...

5 months ago

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Given a window, how many subsets of a vector sum positive

Given a vector: [1 0 -1 3 2 -3 1] and a window of 2, A sliding window would find: 1 + 0 = 1 0 - 1 = -1 ...

5 months 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...

5 months ago

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Find vampire numbers

A <http://en.wikipedia.org/wiki/Vampire_number vampire number> is a number v that is the product of two numbers x and y such th...

5 months ago

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Factorize THIS, buddy

List the prime factors for the input number, in decreasing order. List each factor only once, even if the factorization includes...

5 months 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...

5 months ago

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Multiples of a Number in a Given Range

Given an integer factor _f_ and a range defined by _xlow_ and _xhigh_ inclusive, return a vector of the multiples of _f_ that fa...

5 months ago

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Prime factor digits

Consider the following number system. Calculate the prime factorization for each number n, then represent the prime factors in a...

5 months ago

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Find out sum and carry of Binary adder

Find out sum and carry of a binary adder if previous carry is given with two bits (x and y) for addition. Examples Previo...

5 months ago

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Relative ratio of "1" in binary number

Input(n) is positive integer number Output(r) is (number of "1" in binary input) / (number of bits). Example: * n=0; r=...

5 months ago

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Binary code (array)

Write a function which calculates the binary code of a number 'n' and gives the result as an array(vector). Example: Inpu...

5 months ago

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Converting binary to decimals

Convert binary to decimals. Example: 010111 = 23. 110000 = 48.

5 months ago

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There are 10 types of people in the world

Those who know binary, and those who don't. The number 2015 is a palindrome in binary (11111011111 to be exact) Given a year...

5 months ago

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Bit Reversal

Given an unsigned integer _x_, convert it to binary with _n_ bits, reverse the order of the bits, and convert it back to an inte...

5 months ago

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Given an unsigned integer x, find the largest y by rearranging the bits in x

Given an unsigned integer x, find the largest y by rearranging the bits in x. Example: Input x = 10 Output y is 12 ...

5 months ago

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Binary numbers

Given a positive, scalar integer n, create a (2^n)-by-n double-precision matrix containing the binary numbers from 0 through 2^n...

5 months ago

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Convert given decimal number to binary number.

Convert given decimal number to binary number. Example x=10, then answer must be 1010.

5 months ago