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Implement simple rotation cypher
If given a letter from the set: [abc...xyz] and a shift, implement a shift cypher. Example: 'abc' with a shi...

7 years ago

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How long is the longest prime diagonal?
Stanislaw Ulam once observed that if the counting numbers are <http://en.wikipedia.org/wiki/Ulam_spiral arranged in a spiral>, t...

7 years ago

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Spot the outlier
All points except for one lie on a line. Which one is the outlier? Example: You are given a list of x-y pairs in a column ...

7 years ago

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Make a run-length companion vector
Given a vector x, return a vector r that indicates the run length of any value in x. Each element in r shows how many times the ...

7 years ago

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How many trades represent all the profit?
Given a list of results from trades made: [1 3 -4 2 -1 2 3] We can add them up to see this series of trades made a profit ...

7 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

7 years ago

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Set the array elements whose value is 13 to 0
Input A either an array or a vector (which can be empty) Output B will be the same size as A . All elements of A equal to 13...

7 years ago

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Pernicious Anniversary Problem
Since Cody is 5 years old, it's pernicious. A <http://rosettacode.org/wiki/Pernicious_numbers Pernicious number> is an integer w...

7 years 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...

7 years ago

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Produce a cosine wave
Produce the following signal: <<http://blogs.mathworks.com/images/seth/cody/cosine-eqn.png>>

7 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...

7 years ago

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Add a block to a model
Produce the following signal: <<http://blogs.mathworks.com/images/seth/cody/add-block-eqn.png>> In this case, the slope of...

7 years ago

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Energy of a photon
*&#9883 &#9762 &#9883 &#9762 &#9883 &#9762 &#9883* Given the frequency F of a photon in giga hertz. Find energy E of this...

7 years ago

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How to subtract?
*&plusmn &plusmn &plusmn &plusmn &plusmn &plusmn &plusmn &plusmn &plusmn &plusmn &plusmn* * Imagine you need to subtract one...

7 years ago

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The Goldbach Conjecture, Part 2
The <http://en.wikipedia.org/wiki/Goldbach's_conjecture Goldbach conjecture> asserts that every even integer greater than 2 can ...

8 years ago

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Number of Horns on a unicorn!
Calculate the number of horns on a *unicorn*! And I'm talking about a unicorn with not more than one horn on it!

8 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....

8 years ago

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All capital?
Are all the letters in the input string capital letters? Examples: 'MNOP' -> 1 'MN0P' -> 0

8 years ago

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First N Perfect Squares
*Description* Return the first N perfect squares *Example* input = 4; output = [ 1 4 9 16 ];

8 years ago

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Add two numbers
Calculate the sum of two numbers. Example input = [2 3] output = 5

8 years ago

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Program an exclusive OR operation with logical operators
Program an exclusive or operation *without* using the MATLAB function xor. Use logical operators like |, &, ~, ... instead. ...

8 years ago

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given 3 sides, find area of this triangle
1:3 -> 0; 3:5 -> 6

8 years ago

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Back to basics 11 - Max Integer
Covering some basic topics I haven't seen elsewhere on Cody. Return the largest positive integer MATLAB can handle.

8 years ago

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Given a window, how many subsets of a vector sum positive
Given a vector: [1 0 -1 3 2 -3 1] and a window of 2, A sliding window would find: 1 + 0 = 1 0 - 1 = -1 ...

8 years ago

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Back to basics 22 - Rotate a matrix
Covering some basic topics I haven't seen elsewhere on Cody. Rotate the input matrix 90 degrees counterclockwise (e.g. [1 2; ...

8 years ago

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Extract leading non-zero digit
<http://en.wikipedia.org/wiki/Benford%27s_law Benford's Law> states that the distribution of leading digits is not random. This...

8 years ago

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Find a Pythagorean triple
Given four different positive numbers, a, b, c and d, provided in increasing order: a < b < c < d, find if any three of them com...

8 years ago

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Triangle sequence
A sequence of triangles is constructed in the following way: 1) the first triangle is Pythagoras' 3-4-5 triangle 2) the s...

8 years ago

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Sums with Excluded Digits
Add all the integers from 1 to n in which the digit m does not appear. m will always be a single digit integer from 0 to 9. no...

8 years ago

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Indexed Probability Table
This question was inspired by a Stack Overflow question forwarded to me by Matt Simoneau. Given a vector x, make an indexed pro...

8 years ago