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Zero Cross
Write a function that counts the number of times n a signal x changes sign. Examples x = [1 2 -3 -4 5 6 -7 8 -9 10 11] ...

4 years ago

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Weave two matrices together to form one matrix
Take the first column from matrix a, then insert the first column from matrix b, and so on. For example: a = [1 2 3 4]; b ...

4 years ago

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Rotate matrix by -90 degrees
Rotate a Matrix by -90 degrees Example: X = 1 2 3 4 5 6 7 8 9 output = 7 4 ...

4 years ago

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Replace Nonzero Numbers with 1
Given the matrix x, return the matrix y with non zero elements replaced with 1. Example: Input x = [ 1 2 0 0 0 ...

4 years 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.

4 years ago

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Multiples of a Number in a Given Range
Given an integer factor _f_ and a range defined by _xlow_ and _xhigh_ inclusive, return a vector of the multiples of _f_ that fa...

4 years ago

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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 ...

4 years ago

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Get all prime factors
List the prime factors for the input number, in decreasing order. List each factor. If the prime factor occurs twice, list it as...

4 years ago

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

4 years 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...

4 years ago

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Pascal's pyramid
In Pascal's triangle each number is the sum of the two nearest numbers in the line above: 1 1 1 ...

4 years ago

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Change the sign of even index entries of the reversed vector
change the signs of the even index entries of the reversed vector example 1 vec = [4 -1 -2 9] ans = [9 2 -1 -4] example2...

4 years ago

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Find last zero for each column
Given a numeric array of arbitrary size, return the row index of the last zero for each column. If a column contains all nonzero...

4 years ago

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Numbers spiral diagonals (Part 1)
Inspired by Project Euler n°28 et 58. A n x n spiral matrix is obtained by starting with the number 1 and moving to the right...

4 years ago

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Calendar Matrix
Return a calendar matrix for the given values of month and year. Assume that Sunday is the first day of the week. The resulting ...

4 years ago

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Rainbow matrix
Create a "rainbow matrix" as described in the following examples Input = 3 Output = [ 1 2 3 2 3 2 ...

4 years ago

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Generate this matrix
Generate the following matrix. n = 2; out = [-4 -3 -2 -1 0 -3 -2 -1 0 1 -...

4 years ago

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Matrix Construction I
Given n, construct a matrix as shown in the example below. Example For n=8, the output should look like this: 1 2 3 4 ...

4 years ago

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Longest run of consecutive numbers
Given a vector a, find the number(s) that is/are repeated consecutively most often. For example, if you have a = [1 2 2 2 1 ...

4 years ago

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Return elements unique to either input
Given two numeric inputs a and b, return a row vector that contains the numbers found in only a or only b, but not both. For ex...

4 years ago

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Reindex a vector
You are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX has integers. Place th...

4 years ago

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Balanced number
Given a positive integer find whether it is a balanced number. For a balanced number the sum of first half of digits is equal to...

4 years ago

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Reverse Run-Length Encoder
Given a "counting sequence" vector x, construct the original sequence y. A counting sequence is formed by "counting" the entrie...

4 years ago

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Matrix spiral
Make a spiral in a (n*n) matrix. The spiral has to start in the top left, and has to rotate clockwise to the center. The spiral ...

4 years ago

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Spiral In
Create an m by n matrix filled with sequential integers starting from 1 and arranged in a counterclockwise spiral that hugs the ...

4 years ago

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Create a patchwork matrix
This function will assemble a large matrix out of a number of smaller ones m1, m2, etc., according to a pattern P. If P is 3x5,...

4 years ago

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Alphabetize by last name
Given a list of names in a cell array, sort the list by the last name. So if list = {'Barney Google','Snuffy Smith','Dagwood ...

4 years 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...

4 years ago

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middleAsColumn: Return all but first and last element as a column vector
Given input A, return all but the first and last elements, arranged as a column vector. (I.e., all dimensions after the first s...

4 years ago

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First non-zero element in each column
For a given matrix, calculate the index of the first non-zero element in each column. Assuming a column with all elements zero ...

4 years ago