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Matrix multiplication across rows

Given matrix m, return matrix n such that, rows of n are result of multiplication of the rows of the input matrix Example ...

5 months ago

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A matrix of extroverts

Now that the introverts have had their script, the extroverts spoke up (naturally!) and demanded one as well. You will be given...

5 months ago

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Convert matrix to 3D array of triangular matrices

Given a 2D numeric array x in which each column represents the vectorized form of an upper triangular matrix, return a 3D array ...

5 months ago

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Too Many Zeros, Dump Them!

Sometimes when I create a matrix, I use this syntax: a = zeros(1000,1000); But when the function ends, I find that I don'...

5 months ago

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Enlarge array

Given an m-by-n numeric array (A) and a 1-by-2 vector (sz) indicating the dimensions [p q] to enlarge each element, return an (m...

5 months ago

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Remove entire row and column in the matrix containing the input values

Remove the entire row and column from the matrix containing specific values. The specified value can be a scalar or a vector. Fo...

5 months ago

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MatCAT - Reconstruct X from Its X-rays

Consider a matrix x x = [ 1 2 0 0 5 0 3 0 8 ] If we sum x along the rows we get row_sums = [3 5 11] ...

5 months 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.

5 months ago

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Given a matrix, swap the 2nd & 3rd columns

If a = [1 2 3 4; 1 2 3 4; 1 2 3 4; 1 2 3 4]; then the result is ans = 1 3 2 4 1 3 2...

5 months ago

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matrix zigzag

Unfold a 2-D matrix to a 1-D array in zig-zag order, e.g., for matrix [ 1 2 3 ; 4 5 6 ; 7 8 9 ] the resulting 1-...

5 months ago

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Project Euler: Problem 11, Largest product in a grid

What is the greatest product of _k_ adjacent numbers in the same direction (up, down, left, right, or diagonally) in a _n×n_ gri...

5 months ago

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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...

5 months ago

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Project Euler: Problem 10, Sum of Primes

The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below the input, N. Thank you <http:/...

5 months ago

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Project Euler: Problem 9, Pythagorean numbers

A Pythagorean triplet is a set of three natural numbers, a b c, for which, a^2 + b^2 = c^2 For example, 3^2 + 4^2 =...

5 months ago

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Project Euler: Problem 8, Find largest product in a large string of numbers

Find the greatest product of five consecutive digits in an n-digit number. 73167176531330624919225119674426574742355349194934...

6 months ago

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Project Euler: Problem 7, Nth prime

By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13. What is the Nth prime nu...

6 months ago

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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 ...

6 months ago

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Project Euler: Problem 5, Smallest multiple

2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder. What is the smalle...

6 months ago

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Project Euler: Problem 4, Palindromic numbers

A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 ...

6 months ago

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Project Euler: Problem 3, Largest prime factor

The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number being input, input might be ui...

6 months ago

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Project Euler: Problem 2, Sum of even Fibonacci

Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 te...

6 months ago

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Project Euler: Problem 1, Multiples of 3 and 5

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23...

6 months ago

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Dimensions of a rectangle

The longer side of a rectangle is three times the length of the shorter side. If the length of the diagonal is x, find the width...

6 months ago

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Area of an Isoceles Triangle

An isosceles triangle has equal sides of length x and a base of length y. Find the area, A, of the triangle. <<https://imgur...

6 months ago

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Is this triangle right-angled?

Given three positive numbers a, b, c, where c is the largest number, return *true* if the triangle with sides a, b and c is righ...

6 months ago

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Find a Pythagorean triple

Given four different positive numbers, a, b, c and d, provided in increasing order: a < b < c < d, find if any three of them com...

6 months ago

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Is this triangle right-angled?

Given any three positive numbers a, b, c, return true if the triangle with sides a, b and c is right-angled. Otherwise, return f...

6 months ago

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Triangle sequence

A sequence of triangles is constructed in the following way: 1) the first triangle is Pythagoras' 3-4-5 triangle 2) the s...

6 months ago

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Area of an equilateral triangle

Calculate the area of an equilateral triangle of side x. <<https://i.imgur.com/jlZDHhq.png>> Image courtesy of <http://up...

6 months ago