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Find and replaces spaces from a input string with *
For a given input string str, find how many spaces are there in the string and replace those spaces with * e.g. str = 'this is ...

9 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)....

9 years ago

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Find relatively common elements in matrix rows
You want to find all elements that exist in greater than 50% of the rows in the matrix. For example, given A = 1 2 3 5 ...

9 years ago

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Area of a triangle
A triangle is given with base *'b'* ,vertical hight *'h'* . then find it's area.

9 years ago

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Number of 1s in a binary string
Find the number of 1s in the given binary string. Example. If the input string is '1100101', the output is 4. If the input stri...

9 years ago

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Create a vector whose elements depend on the previous element
The idea is to create a vector A whose elements depend on the previous element : *A(i+1) = 2*A(i)+1* *2 Inputs*: - A : The...

9 years ago

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Do Fast Fourier Transformation
Example Fast Fourier Transformation from vector [2,1]) ans = 3 1

9 years ago

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System of equations
Find a solution to a system of equations represented by a |n| by |n+1| matrix. For instance, [ 2 0 4; => 2*x = 4 ...

9 years ago

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Triangle Numbers Below N
This is an offshoot of <http://www.mathworks.com/matlabcentral/cody/problems/5-triangle-numbers Cody Problem 5: Triangle Numbers...

9 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...

9 years ago

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N-Queens Checker
Picture a chessboard populated with a number of queens (i.e. pieces that can move like a queen in chess). The board is a matrix,...

9 years ago

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Matrix which contains the values of an other matrix A at the given locations.
If you have two matrices, which together give xc and yc coordinates into another matrix, eg : xc = [1 1 1; 2 2 1]; ...

9 years ago

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Find the largest value in the 3D matrix
Given a 3D matrix A, find the largest value. Example >> A = 1:9; >> A = reshape(A,[3 1 3]); >> islargest(A) a...

9 years ago

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Magic!
Check whether the input matrix is a normal magic square: <http://en.wikipedia.org/wiki/Magic_square> Output the logical va...

9 years ago

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Function composition
Write a function that accepts two function handles f and g and returns the composition h. That is, h = (f o g)(x) = f(g(x)) ...

9 years ago

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Is A the inverse of B?
Given a matrix A and a matrix B, is A the inverse of B? >>A=[2,4;3,5]; >>B=[-2.5,2;1.5,-1]; >>isInverse...

9 years ago

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Cumulative probability of finding an unlikely combination
This is a supplemental problem to the <http://www.mathworks.com/matlabcentral/cody/problems/621-cryptomath-addition CryptoMath> ...

9 years ago

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String substitution, sub problem to cryptoMath
This is a sub problem related to this problem: <http://www.mathworks.com/matlabcentral/cody/problems/621-cryptomath-addition>...

9 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 ...

9 years ago

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Back and Forth Rows
Given a number n, create an n-by-n matrix in which the integers from 1 to n^2 wind back and forth along the rows as shown in the...

9 years ago

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Multiply 2 numbers
Very easy, you just have to multiply 2 numbers but you cannot use the following signs (*, /, - ,^) ,mtimes , times, cross, pro...

9 years ago

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Target sorting
Sort the given list of numbers |a| according to how far away each element is from the target value |t|. The result should return...

9 years 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...

9 years ago

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Half?
If you toss an even number (x) of coins, what is the probability (y) of 50% head and 50% tail?

9 years ago

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Back to basics 14 - Keywords
Covering some basic topics I haven't seen elsewhere on Cody. Return a cell array of all MATLAB keywords

9 years ago

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Remove the polynomials that have positive real elements of their roots.
The characteristic equation for a dynamic system is a polynomial whose roots indicate its behavior. If any of the <http://www.ma...

9 years 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 ...

9 years ago

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random picture with random colours
write a function which creates a random(x,y) matrix with random RGB colours for example create_pic(5,5) gives us a 3d matrix. ...

9 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...

9 years ago

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Mandelbrot Numbers
The <http://en.wikipedia.org/wiki/Mandelbrot_set Mandelbrot Set> is built around a simple iterative equation. z(1) = c z...

9 years ago