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Rotate a Matrix by 90 degrees
Rotate a Matrix by 90 degrees Example: If the input is: X = 1 2 3 4 5 6 7 8 9 ...

13 years ago

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Determine Whether an array is empty
Input a matrix x, output y is TRUE if x is empty, otherwise FALSE.

13 years ago

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

13 years ago

Solved

Project Euler: Problem 6, Natural numbers, squares and sums.
The sum of the squares of the first ten natural numbers is, 1^2 + 2^2 + ... + 10^2 = 385 The square of the sum of the first ...

13 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...

13 years ago

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Compute a dot product of two vectors x and y
x and y are input vectors, d is a number and contains their dot product

13 years ago

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Back to basics 25 - Valid variable names
Covering some basic topics I haven't seen elsewhere on Cody. Given a string, return true if it is a valid MATLAB variable nam...

13 years ago

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vectorization in N
For a given integer n (n>1), compute the sum f (i) (1 <= i <= n) where f (i) = 1 if n is odd and 2 otherwise.

13 years ago

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Getting the indices from a vector
This is a basic MATLAB operation. It is for instructional purposes. --- You may already know how to <http://www.mathworks....

13 years ago

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Back to basics 26 - Keywords
Covering some basic topics I haven't seen elsewhere on Cody. Return a cell array of strings of all MATLAB keywords.

13 years ago

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Matrix indexing with two vectors of indices
Given a matrix M and two index vectors a and b, return a row vector x where x(i) = M(a(i),b(i)).

13 years ago

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Construct a string from letters and counts
Given two input arrays like this: [5,3,1] ['a','b','c'] Output a string that contains each letter the specified num...

13 years ago

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Get the length of a given vector
Given a vector x, the output y should equal the length of x.

13 years ago

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Multiply a column by a row
* Given a column vector C and and a row vector R. * Output a matrix M. * Every column of M equals to C multiplied by correspon...

13 years ago

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Back to basics 13 - Input variables
Covering some basic topics I haven't seen elsewhere on Cody. Return as a string the name of the input variable to the functio...

13 years ago

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Return the first and last character of a string
Return the first and last character of a string, concatenated together. If there is only one character in the string, the functi...

13 years ago

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Create a square matrix of multiples
Given an input, N, output a matrix N x N with each row containing multiples of the first element of each row. This also applies...

13 years ago

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Convert a vector into a number
This is a sub problem related to this problem: <http://www.mathworks.com/matlabcentral/cody/problems/621-cryptomath-addition>...

13 years ago

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Replace May with April
For instance, if the input is input_str = 'The flowers may bloom in April'; then the output is output_str = 'The flo...

13 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 ...

13 years ago

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Angle between two vectors
You have two vectors , determine the angle between these two vectors For example: u = [0 0 1]; v = [1 0 0]; The a...

13 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...

13 years ago

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Who knows the last digit of pi?
There is only one man who knows the last digit of pi, who is that man? Give the name of that man, who, by popular believe, can ...

13 years ago

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Scoring for oriented dominoes
Given a list of ordered pairs, and the order they should be placed in a line, find the sum of the absolute values of the differe...

13 years ago

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Love triangles
Given a vector of lengths [a b c], determines whether a triangle with non-zero area (in two-dimensional Euclidean space, smarty!...

13 years ago

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2 b | ~ 2 b
Given a string input, output true if there are 2 b's in it, false if otherwise Examples: 'Macbeth' -> false 'Publius Cor...

14 years ago

Solved

Solve the set of simultaneous linear equations
Given this pair of simultaneous linear equations: 2x + 3y = 23 3x + 4y = 32 Find the solution set (x,y)

14 years ago

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Create a function handle that reverses the input arguments of another function handle
Given a function that takes two input arguments and returns one output, create another function handle that performs the same op...

14 years ago

Solved

Get the area codes from a list of phone numbers
Given a string of text with phone numbers in it, return a unique'd cell array of strings that are the area codes. s = '508-647...

14 years ago

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Geometric series
Find the sum, given the first term t1, the common ratio r, and number of terms n. Examples If input t1=1, r=1, n=7 the...

14 years ago