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Days until next NewYear ball drop
Given a date string in the form 'yyyy-mm-dd' or 'yyyy-mm-dd hh:mm:ss', calculate the number of *days* until the dropping of the ...

3 years ago

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Reverse the elements of an array
Reverse the order of elements in an array: eg: input X = [ 1 2 3 ; 4 5 6 ; 7 8 9 ] o...

3 years ago

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Operate on matrices of unequal, yet similar, size
You may want to add a vector to a matrix, implying that the vector is added to each column of the matrix. Or multiply a 3x4x5 ma...

3 years ago

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Permute diagonal and antidiagonal
Permute diagonal and antidiagonal For example [1 2 3;4 5 6;7 8 9] -> [3 2 1;4 5 6;9 8 7] WITHOUT diag function (and variable n...

3 years ago

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Rotate input square matrix 90 degrees CCW without rot90
Rotate input matrix (which will be square) 90 degrees counter-clockwise without using rot90,flipud,fliplr, or flipdim (or eval)....

3 years ago

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Removing rows from a matrix is easy - but what about inserting rows?
Assume A is a 5-by-5 matrix. A([2,4],:) = [] is a quick way to remove rows 2 and 4. Can you find a quick way to insert rows into...

3 years ago

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Matrix with different incremental runs
Given a vector of positive integers a = [ 3 2 4 ]; create the matrix where the *i* th column contains the vector *1:a(i)...

3 years ago

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Set some matrix elements to zero
First get the maximum of each *row*, and afterwards set all the other elements to zero. For example, this matrix: 1 2 3 ...

3 years ago

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surrounded matrix
With a given matrix A (size m x n) create a matrix B (size m+2 x n+2) so that the matrix A is surrounded by ones: A = [1 2 ...

3 years ago

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Flip the main diagonal of a matrix
Given a n x n matrix, M, flip its main diagonal. Example: >> M=magic(5); >> flipDiagonal(M) 9 24 1 ...

3 years ago

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Remove the air bubbles
Given a matrix a, return a matrix b in which all the zeros have "bubbled" to the top. That is, any zeros in a given column shoul...

3 years ago

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Make an awesome ramp for a tiny motorcycle stuntman
Okay, given a vector, say v=[1 3 6 9 11], turn it into a matrix 'ramp' like so: m=[1 3 6 9 11; 3 6 9 11 0; 6 9 ...

3 years ago

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Back to basics 23 - Triangular matrix
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, return a matrix with all elements above a...

3 years ago

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Back to basics 21 - Matrix replicating
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, generate an output matrix that consists o...

3 years ago

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Remove NaN ?
input -> matrix (n*m) with at least one element equal to NaN; output -> matrix(p*m), the same matrix where we deleted the enti...

3 years ago

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Is the Point in a Triangle?
Check whether a point or multiple points is/are in a triangle with three corners Points = [x, y]; Triangle = [x1, y1; x...

3 years ago

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Can we make a triangle?
Given three positive number, check whether a triangle can be made with these sides length or not. remember that in a triangle su...

3 years ago

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Find the sides of an isosceles triangle when given its area and height from its base to apex
Find the sides of an isosceles triangle when given its area and the height from its base to apex. For example, with A=12 and ...

3 years ago

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Height of a right-angled triangle
Given numbers a, b and c, find the height of the right angled triangle with sides a and b and hypotenuse c, for the base c. If a...

3 years ago

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Right Triangle Side Lengths (Inspired by Project Euler Problem 39)
If _p_ is the perimeter of a right angle triangle with integral length sides, { _a_, _b_, _c_ }, there are exactly three solutio...

3 years ago

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Find my daddy long leg (No 's')
Given the ratio of the two legs (longer / shorter), and the hypotenuse length, find the value of the bigger leg.

3 years ago

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Calculate the area of a triangle between three points
Calculate the area of a triangle between three points: P1(X1,Y1) P2(X2,Y2) P3(X3,Y3) these three points are the vert...

3 years 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...

3 years 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...

3 years 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...

3 years 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...

3 years 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...

3 years 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...

3 years ago

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Side of an equilateral triangle
If an equilateral triangle has area A, then what is the length of each of its sides, x? <<https://i.imgur.com/jlZDHhq.png>> ...

3 years ago

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Side of a rhombus
If a rhombus has diagonals of length x and x+1, then what is the length of its side, y? <<https://imgur.com/x6hT6mm.png>> ...

3 years ago