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Gauss Eliminate 2-by-2 example
Use forward elimination to make the coefficient matrix, A, an upper triangular matrix, and then solve using back substitution, f...

8 years ago

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How many days in a month?
Return the number of days in a given month in 2017. If the input is not a valid month number, return -1. Examples: Input...

8 years ago

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hanoi towers II
with 3 rods (1,2 & 3), the goal is to move a tower of n disks from rod #1 to rod #3. You can move disks only one by one, on the...

8 years ago

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Minimum Maximum Sort Array
sort one array by put minimum value followed by maximum as follow a=[2 3 1 5] and the solution is y=[1 5 2 3 3 2 5 1];

8 years ago

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Create matrix with Gray code
Output "g" should be a matrix of class double, with <http://en.wikipedia.org/wiki/Gray_code Gray reflected binary code>. Inpu...

8 years ago

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Is this date a palindrome?emordnilap a etad siht sI
Take a MATLAB date number as input, and return true if the date is a palindrome, false if the date is not a palindrome. A date ...

8 years ago

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Set a Soroban Abacus
*Description* This problem is the inverse of <http://www.mathworks.com/matlabcentral/cody/problems/136-read-a-soroban-abacus ...

8 years ago

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Four quadrant inverse tangent function.
Create a function that returns an array P the same size as X and Y containing the element-by-element, four-quadrant inverse tang...

8 years ago

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resistor ladder
* You have a bunch (an odd number N) of identical resistors (each R ohms), a good battery (V volts), and a high impedance voltme...

8 years ago

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Specific toolboxes
Given a string that is the name of a MATLAB toolbox, return true if it is available on the Cody solvers evaluation system, false...

8 years ago

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Find last non-zero in a given dimension
You are given a logical matrix *BW* _of any dimension_, and a dimension *dim*. You need to find the locations of the last non-ze...

8 years ago

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root?
* Given a function 'foo', and a position 'there', find the root near 'there'. * For example: If foo=@sin, and there=3.1, then r...

8 years ago

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Nilpotent matrix
Check if matrix A is <http://mathworks.com/ nilpotent>.

8 years ago

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Set defaults
Write a function that computes the volume of a cube. The function should be able to accept three inputs: the length, width, and...

8 years ago

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Vector Linear sum: (p1-m1)V1+(p2-m2)V2+...(pK-mk)Vk
Calculate the sum of a Vector times coefficients expressed as two strings. Example: Normal representation [ a b c ], [ p1 ...

8 years ago

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Accumulate Cells
Given a combining function, a cell array, and an initial value, accumulate the result. For example, accumcell(@plus,{1,...

8 years ago

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Create a matrix from a cell
In this problem , you must convert a cell into a matrix and pad each cell with NaN. *Example 1:* If you have the input...

8 years ago

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Sum the entries of each column of a matrix which satisfy a logical condition.
Given a numeric matrix A and a logical array L of the same size as A, return a row vector S containing the columnwise sums of th...

8 years ago

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Create array of all Distances between two Sets of Points
This Challenge is a subsection of <http://www.mathworks.com/matlabcentral/cody/problems/1110-usc-fall-2012-acm-martian-pranks Ma...

8 years ago

Solved

Create array of all Distances between two Sets of Points : No Neural Network Toolbox
This Challenge is a subsection of <http://www.mathworks.com/matlabcentral/cody/problems/1110-usc-fall-2012-acm-martian-pranks Ma...

8 years ago

Solved

Happy 2013...
Happy 2013, everyone! An interesting tidbit about 2013 is that it is the first year since 1987 to contain four different digits...

8 years ago

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Get ranks of values in a vector
For a given vector, say [6 3 8 2], return the ranks (ascending) of observations, i.e. [3 2 4 1]. Do not worry about tied ranks. ...

8 years ago

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Create a recurrence matrix for a vector of data
In <https://en.wikipedia.org/wiki/Conversation_analysis conversation analysis>, it's often useful to track the contributions fro...

8 years ago

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Decrypt a secret message!
The crypto system in question is based on phone keyboard. We need two numbers in order to decrypt a word. First number represent...

8 years ago

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String permutations on phone keyboard
Given a number such as 2639 return all possible string permutations using the phone-keyboard on <http://www.mathworks.com/matlab...

8 years ago

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Phoneword Translator
Given an alphanumeric telephone number (Ex. 1-800-COLLECT), return the purely numeric phone number as a vector. This problem use...

8 years ago

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Apply a function array to an array of numbers
It is required to apply a cell array of functions to a numerical array, where the functions accept only scalar inputs. Exampl...

8 years ago

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Friday the 13th
According to superstition, lots of unpleasant stuff happens on Friday the 13th, so you might like to find the next occurence of ...

8 years ago

Solved

Convert elements in numeric array into different class
Write a function that converts elements in a numeric array into a different class. Example: a = [1:5]; % class: double b...

8 years ago

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Method of Common Differences part-2
This is the inverse problem to <http://www.mathworks.com/matlabcentral/cody/problems/1485 Problem 1485>. Problem 1485 illustra...

8 years ago