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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'...

2 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...

2 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...

2 months ago

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frame of the matrix
Given the matrix M, return M without the external frame.

2 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.

2 months ago

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Matrix of Multiplication Facts
This is James's daughter again, sneaking into his Cody account. Thanks to your help in my math class last year, I did great! But...

2 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...

2 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-...

2 months 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...

2 months 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...

2 months 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...

2 months 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...

2 months 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)....

2 months 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)...

2 months 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 ...

2 months 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 ...

2 months 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 ...

2 months 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 ...

2 months 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...

2 months 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...

2 months 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. ...

2 months 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...

2 months 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...

2 months ago

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Decimation - Optimized for speed
This problem is similar to http://www.mathworks.com/matlabcentral/cody/problems/1092-decimation, only this time the score will b...

2 months ago

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Decimation
When dealing to the Roman Army, the term decimate meant that the entire unit would be broken up into groups of ten soldiers, and...

2 months ago

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Finding peaks
Find the peak values in the signal. The peak value is defined as the local maxima. For example, x= [1 12 3 2 7 0 3 1 19 7]; ...

2 months ago

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Max index of 3D array
Given a three dimensional array M(m,n,p) write a code that finds the three coordinates x,y,z of the Maximum value. Example ...

2 months ago

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Determine the number of odd integers in a vector
Determine the number of unique odd integers in a vector. Examples: Input x = [2 5 8 3 7 1]; Output y = 4; Inp...

2 months ago

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Reference Index Number
Given a reference set R of elements (each unique but identical in type), and a list V of elements drawn from the set R, possibly...

2 months ago

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Insert zeros into vector
Insert zeros after each elements in the vector. Number of zeros is specified as the input parameter. For example: x = [1 ...

2 months ago