djb

Last seen: circa 2 anni fa | Attivo dal 2023

Followers: 0 Following: 0

Statistica

Feeds

Risolto

Compute the Sequence of the Day
A sequence starts with 1 and 2, and each subsequent term is the sum of the digits of the product of the previous two terms. As a...

circa 2 anni fa

Risolto

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 = [...

circa 2 anni fa

Risolto

Hexagonal numbers on a spiral matrix
Put hexagonal numbers in a ( m x m ) spiral matrix and return the sum of its diagonal elements. Formula of hexagonal numbers ...

circa 2 anni fa

Risolto

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

circa 2 anni fa

Risolto

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...

circa 2 anni fa

Risolto

Twin Primes
Twin primes are pairs of primes that are immediately next to each other (difference of two). The lesser of twin primes are 3, 5,...

circa 2 anni fa

Risolto

Diophantine Equations (Inspired by Project Euler, problem 66)
Consider the quadratic Diophantine equation of the form: x^2 – Dy^2 = 1 When D=13, the minimal solution in x is 649^2 – 13...

circa 2 anni fa

Risolto

Joining Ranges
You are given a n-by-2 matrix. Each row represents a numeric range, e.g. x = [0 5; 10 3; 20 15; 16 19; 25 25] contains...

circa 2 anni fa

Risolto

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...

circa 2 anni fa

Risolto

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...

circa 2 anni fa

Risolto

Balanced number
Given a positive integer find whether it is a balanced number. For a balanced number the sum of first half of digits is equal to...

circa 2 anni fa

Risolto

Number of even divisors of a given number
Given a Number n, return the number of its even divisors without listing them. example: n=14 ; EvenDivisors={2,14} ; y=2 ...

circa 2 anni fa

Risolto

Smith numbers
Return true if the input is a Smith number in base ten. Otherwise, return false. Read about Smith numbers at http://en.wikipedia...

circa 2 anni fa

Risolto

A different counting method
Given an array (x) of integers, the "counting" array (y) is showing the number of identical consecutive integers in x in front o...

circa 2 anni fa

Risolto

Number of Circles in a Number
Given a number, return the number of closed 'circles' in the base 10 numerical representation. Note: the number 4 has no circ...

circa 2 anni fa

Risolto

Hankelize a matrix
Similar to <http://www.mathworks.com/matlabcentral/cody/problems/42501-toeplitize-a-matrix Problem 42501. Toeplitize a matrix>, ...

circa 2 anni fa

Risolto

It dseon't mettar waht oedrr the lrettes in a wrod are.
An internet meme from 2003 (read more here) asserted that readers are relatively insensitive to letter order in words, so long a...

circa 2 anni fa

Risolto

Construct a prime circle
A <https://mathworld.wolfram.com/PrimeCircle.html prime circle> is a circular arrangement of the numbers 1 to 2n such that pairs...

circa 2 anni fa