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John D'Errico


Retired

Last seen: Today Attivo dal 2006

DON'T contact me. I won't answer questions. PERIOD. I don't do your homework. I won't do consulting. A retired mathematician, numerical analyst, woodworker, bridge player.

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Risolto


Divisible by 2
This is the first problem in a set of "divisible by x" problems. You will be provided a number as a string and the function you ...

oltre un anno fa

Risolto


Edges of a n-dimensional Hypercube
Return the number of edges on an <http://en.wikipedia.org/wiki/Hypercube _n_-dimensional hypercube> (with an integer n &ge; 0). ...

oltre 4 anni fa

Risolto


Dots in a Circle
Return how many integer grid points there are inside a circle of radius _r_ centred at (0,0) (including points on the edge). ...

oltre 4 anni fa

Risolto


The average of the second largest values
Given a matrix, find the average of the second largest values in each row. The same value does not exist on a row. Example: ...

circa 5 anni fa

Risolto


Fibonacci-Sum of Squares
Given the Fibonacci sequence defined by the following recursive relation, * F_n = F_(n-1) + F_(n-2) * where F_0 = 0 and F_1 ...

circa 5 anni fa

Risolto


Volume of a Simplex
Return the volume of a <http://en.wikipedia.org/wiki/Simplex regular _n_-simplex> with a unit side length. Results are up to...

circa 5 anni fa

Risolto


Volume difference between Ellipsoid and Sphere
Given an ellipsoid of semi principal axis (a,b,c) find the volume of the difference between this ellipsoid and the sphere with...

circa 5 anni fa

Risolto


Perimeter
Given a sequence of points forming a closed path (first and last points are coincident) return the perimeter value. For example...

circa 5 anni fa

Risolto


Return the Fibonacci Sequence
Write a code which returns the Fibonacci Sequence such that the largest value in the sequence is less than the input integer N. ...

circa 5 anni fa

Risolto


Find nearest prime number less than input number
Find nearest prime number less than input number. For example: if the input number is 125, then the nearest prime number whi...

circa 5 anni fa

Risolto


sum of non-primes
The sum of the non-primes no larger than 10 is 1+4+6+8+9+10=38 Find the sum of all the positive non-prime integers that do no...

circa 5 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 5 anni fa

Risolto


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

circa 5 anni fa

Risolto


Get linearly independent vectors of given matrix.
Get a set of linearly independent vectors from the rows of a given matrix. Example matrix=[ 3 -1 0 0 ; ...

circa 6 anni fa

Problema


Euclidean distance from a point to a polynomial
A not uncommon problem in the area of computational geometry is to find the closest point to a straight line from a given point,...

circa 6 anni fa | 2 | 25 risolutori

Risolto


For given xx,x, y vectors build spline of x and y and find yy values for xx vector.
For given xx,x, y vectors build spline of x and y and find yy values for xx vector. Example x = [ 1.0000 1.5000 2.00...

circa 6 anni fa

Risolto


What's size of TV?
Many people buy TV. Usually they ask about diagonal. But also important are width and height. Let's assume that all TV have rati...

circa 6 anni fa

Problema


Euclidean inter-point distance matrix
The Euclidean distance between two points in a p-dimensional space is a really common thing to compute in the field of computati...

circa 6 anni fa | 1 | 21 risolutori

Risolto


Prime number removal
remove all prime numbers from the input e.g. input = 1 2 3 4 5 6 7 8 9 10 11 12 ...

circa 6 anni fa

Risolto


Determine the roots of a cubic equation
Given the coefficients a, b, c, and d of a cubic equation, a*x^3 + b*x^2 + c*x + d = 0, determine its roots.

circa 6 anni fa

Risolto


Roots of a quadratic equation.
Calculate the roots of a quadratic equation, given coefficients a, b, and c, for the equation a*x^2 + b*x + c = 0.

circa 6 anni fa

Risolto


Sum of digits of powers of 2
Given n, first, calculate the number 2^n. Then, sum the digits that comprise that number. For example: Input: n = 7 2^n = ...

circa 6 anni fa

Problema


Simpsons's rule (but not Homer Simpson)
I wonder what Homer Simpson would have thought of Simpson's rule? Somehow I doubt his thoughts would have included the phrase Ne...

circa 6 anni fa | 4 | 30 risolutori

Risolto


Right and wrong
Given a vector of lengths [a b c], determines whether a triangle with those sides lengths is a right triangle: <http://en.wikipe...

circa 6 anni fa

Risolto


Make a Palindrome Number
Some numbers like 323 are palindromes. Other numbers like 124 are not. But look what happens when we add that number to a revers...

circa 6 anni fa

Risolto


Solve the Sudoku Row
*Description* A simple yet tedious task occurs near the end of most Sudoku-solving algorithms, computerized or manual. The ta...

circa 6 anni fa

Risolto


Sums of cubes and squares of sums
Given the positive integers 1:n, can you: 1. Compute twice the sum of the cubes of those numbers. 2. Subtract the square...

oltre 6 anni fa

Problema


Sums of cubes and squares of sums
Given the positive integers 1:n, can you: 1. Compute twice the sum of the cubes of those numbers. 2. Subtract the square...

oltre 6 anni fa | 8 | 198 risolutori

Risolto


Project Euler: Problem 6, Natural numbers, squares and sums.
The sum of the squares of the first ten natural numbers is, 1^2 + 2^2 + ... + 10^2 = 385 The square of the sum of the first ...

oltre 6 anni fa

Risolto


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

oltre 6 anni fa

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