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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 ...

3 years ago

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

3 years 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...

3 years ago

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Add two numbers
Given a and b, return the sum a+b in c.

3 years ago

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Swap the first and last columns
Flip the outermost columns of matrix A, so that the first column becomes the last and the last column becomes the first. All oth...

3 years ago

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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 displayed ...

3 years ago

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Indexed Probability Table
This question was inspired by a Stack Overflow question forwarded to me by Matt Simoneau. Given a vector x, make an indexed pro...

3 years ago

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Select every other element of a vector
Write a function which returns every other element of the vector passed in. That is, it returns the all odd-numbered elements, s...

3 years ago

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Find common elements in matrix rows
Given a matrix, find all elements that exist in every row. For example, given A = 1 2 3 5 9 2 5 9 3 2 5 9 ...

3 years ago

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Return a list sorted by number of occurrences
Given a vector x, return a vector y of the unique values in x sorted by the number of occurrences in x. Ties are resolved by a ...

3 years ago

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Fibonacci sequence
Calculate the nth Fibonacci number. Given n, return f where f = fib(n) and f(1) = 1, f(2) = 1, f(3) = 2, ... Examples: Input...

3 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...

3 years ago

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Find the peak 3n+1 sequence value
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...

3 years ago

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Given two arrays, find the maximum overlap
Given two (integer) arrays s1 and s2, create a new array s3 which is as short as possible and contains both arrays. #1 s1 = [...

3 years ago

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Kaprekar Steps
6174 is the Kaprekar constant. All natural numbers less than 10,000 (except some with same digits) can be reduced to 6174 in the...

3 years ago

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Generate this matrix
For a given odd integer n, generate a matrix as follows: Input: n = 5; Output: [ 2 1 0 0 0 1 ...

4 years ago

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Calendar Matrix
Return a calendar matrix for the given values of month and year. Assume that Sunday is the first day of the week. The resulting ...

4 years ago

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Rainbow matrix
Create a "rainbow matrix" as described in the following examples Input = 3 Output = [ 1 2 3 2 3 2 ...

4 years ago

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Generate this matrix
Generate the following matrix. n = 2; out = [-4 -3 -2 -1 0 -3 -2 -1 0 1 -...

4 years ago

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Pascal's pyramid
In Pascal's triangle each number is the sum of the two nearest numbers in the line above: 1 1 1 ...

4 years ago

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Numbers spiral diagonals (Part 2)
Inspired by Project Euler n°28 and 58. A n x n spiral matrix is obtained by starting with the number 1 and moving to the right ...

4 years ago

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Toeplitz Matrix
For a given square matrix of order n-by-n check whether this is a Toeplitz matrix or not. Return true if it is.

4 years ago

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ZigZag matrix with reflected format
ZigZag MATRIX with REFLECTED format. We have only input x. We have to create a matrix in the following pattern. input n=5...

4 years ago

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Diagonal of a Spiral Matrix
Write a function that will return same output as diag(spiral(n)). The only exception is that spiral and diag functions are not a...

4 years 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...

4 years ago

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Binary Neighbourhood
Given a natural number reorder its binary form to create another number, closest to the given one. Examples: * 1 gives 2, ...

4 years ago

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Big numbers, repeated least significant digits
This problem builds off of Problem 3077 Given an integer x which contains d digits, find the value of (minimum) n (n > 1) such ...

4 years ago

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

4 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.

4 years ago

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Toeplitize a matrix
Similar to <http://www.mathworks.com/matlabcentral/cody/problems/3094-hankelize-a-matrix Problem 3094. Hankelize a matrix>, now ...

4 years ago