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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)....

12 days 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...

12 days 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)...

12 days 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 ...

12 days ago

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Some Assembly Required
The input to this function is a matrix of real numbers. Your job is to assemble the rows of the matrix into one large row that ...

12 days 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 ...

12 days 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 ...

12 days 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 ...

12 days 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...

12 days 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...

12 days ago

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N-Dimensional Array Slice
Given an N-dimensional array, _A_, an index, _I_, and a dimension, _d_, return the _I_ th elements of _A_ in the _d_ dimension. ...

12 days 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...

12 days 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...

12 days ago

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Rescale Scores
Each column (except last) of matrix X contains students' scores in a course assignment or a test. The last column has a weighted...

13 days ago

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Calculate BMI
Given a matrix hw (height and weight) with two columns, calculate BMI using these formulas: 1 kilogram = 2.2 pounds 1 inch = 2...

15 days ago

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Calculate a Damped Sinusoid
The equation of a damped sinusoid can be written as y = A.ⅇ^(-λt)*cos(2πft) where A, λ, and f are scalars and t is a vector. ...

15 days ago

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Solve a System of Linear Equations
Example: If a system of linear equations in x₁ and x₂ is: 2x₁ + x₂ = 2 x₁ - 4 x₂ = 3 Then the coefficient matrix (A) is: 2 ...

15 days ago

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Verify Law of Large Numbers
If a large number of fair N-sided dice are rolled, the average of the simulated rolls is likely to be close to the mean of 1,2,....

15 days ago

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Find the Oldest Person in a Room
Given two input vectors: * |name| - user last names * |age| - corresponding age of the person Return the name of the ol...

15 days ago

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Convert from Fahrenheit to Celsius
Given an input vector F containing temperature values in Fahrenheit, return an output vector C that contains the values in Celsi...

15 days ago

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Calculate Amount of Cake Frosting
Given two input variables r and h, which stand for the radius and height of a cake, calculate the surface area of the cake you n...

15 days ago

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Plot Damped Sinusoid
Given two vectors |t| and |y|, make a plot containing a blue ( |b| ) dashed ( |--| ) line of |y| versus |t|. Mark the minimum...

15 days ago

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Create a matrix map of increasing safety levels
The sole nuclear power plant at Grid City suddenly had a meltdown. Luckily, the plant was designed to be in full automation, so ...

15 days ago

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Similar Triangles - find the height of the tree
Given the height, h1, of a power pole, shorter than a tree, a given distance, x2 away, please find h2, height of the tree. Pleas...

15 days ago

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Determine when snow started
R.P. Agnew posed the following problem: It starts snowing in the morning and continues steadily throughout the day. A snowplow t...

15 days ago

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Air Mass to Star for an Observer at Mean Sea Level
Air mass is a measure of how much atmosphere light from a source above the atmosphere (eg sun, planet, star) has to travel throu...

15 days ago

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Calculate Wind Chill Factor
The NWS Wind Chill Temperature (WCT) index formula for calculating the dangers from winter winds and freezing temperatures: Cal...

15 days ago

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The twelve days of Christmas
Traditionally there are twelve days of Christmas to celebrate ("Twelvetide"), typically starting with Christmas Day (25 December...

15 days ago

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Scrabble Scores
Given a word, determine its score in <http://en.wikipedia.org/wiki/Scrabble Scrabble>. The input string will always be provi...

15 days ago

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Snow Accumulation and Structural Risks To Residential Properties
The density of snow depends on the amount of liquid water it contains: Dry Snow is about 50 kg/m^3 Wet Snow is about 200 kg/m^...

15 days ago