Problem

Determine if input is a perfect number
A <http://en.wikipedia.org/wiki/Perfect_number/ perfect number> occurs whent the sum of all divisors of a positive integer, exce...

14 years ago | 4 | 267 solvers

Solved

Unique: Faster for options 'rows' and 'stable' for large array of uint8
Challenge: Execute unique(a,'rows','stable') Faster for 'a' being uint8. The "unique" function for the 'rows' and 'stable' o...

14 years ago

Solved

Determine if input is a Narcissistic number
<http://en.wikipedia.org/wiki/Narcissistic_number Narcissistic number> is a number that is the sum of its own digits each raised...

14 years ago

Problem

Determine if input is a Narcissistic number
<http://en.wikipedia.org/wiki/Narcissistic_number Narcissistic number> is a number that is the sum of its own digits each raised...

14 years ago | 2 | 220 solvers

Solved

Set a diagonal
Given a matrix M, row vector v of appropriate length, and diagonal index d (where 0 indicates the main diagonal and off-diagonal...

14 years ago

Solved

Unique values without using UNIQUE function
You must return unique values in a vector in *stable* mode without using the unique function. About stable order flag: ...

14 years ago

Solved

Find nearest prime number less than input number
Find nearest prime number less than input number . For example: if the input number is 125, then the nearest prime number whi...

14 years ago

Solved

Eliminate unnecessary polygon vertices
Suppose you have an n-point polygon represented as an n-by-2 matrix of polygon vertices, P. Assume that the polygon is closed; t...

14 years ago

Solved

Solve Quadratic : No * - or key functions permitted
Solve the quadratic equation *ax^2+bx+c=0*. However, some of the normal functions and symbols are not allowed. x=[ -b +/- sq...

14 years ago

Solved

Pi Estimate 1
Estimate Pi as described in the following link: <http://www.people.virginia.edu/~teh1m/cody/Pi_estimation1.pdf>

14 years ago

Solved

We love vectorized solutions. Problem 1 : remove the row average.
Given a 2-d matrix, remove the row average from each row. Your solution MUST be vectorized. The solution will be tested for ac...

14 years ago

Solved

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...

14 years ago

Solved

Cody Matlab Version
What is the current Cody Matlab Release? *Output:* string *Examples:* '(R2012a)' or 'R2012a' Hint: We have mo...

14 years ago

Solved

"mirror" matrix
Create n x 2n "mirror" matrix of this type: e.g. for n = 2 m = [1 2 2 1;1 2 2 1] e.g. for n = 3 m = [1 2 3 3 2 1...

14 years ago

Solved

Script file size
Determine the file size of a script, "function.m". This is the base scoring method for Cody and the Matlab Contests. A met...

14 years ago

Solved

Find the list of all open files
In the test suite, I use <http://www.mathworks.com/help/matlab/ref/fopen.html fopen> to create new files. The task is to find th...

14 years ago

Solved

mathematics , probability problem
How many different result can we have, rolling k dice?

14 years ago

Solved

Fix y_correct : Hack
The Test Suite has an error. Fix the y_correct value. (See the tags for hints)

14 years ago

Solved

intersection of matrices
Given two matrices filled with ones and zeros, determine if they share a common row, column entry. These matrices are of identi...

14 years ago

Solved

Justify the character string in center with proportional fonts
how to justify a string of character into center with proportional fonts? Example: x='justify string ' output is ' justif...

14 years ago

Solved

Calculate the Hamming distance between two strings
Inspired by a similar Cody problem found <http://www.mathworks.com/matlabcentral/cody/problems/93-calculate-the-levenshtein-dist...

14 years ago

Solved

Compute the dilation of a binary image
A basic operation in image analysis is the dilation. Given an image where each pixel is either on or off (black/white, true/fals...

14 years ago

Solved

Find third Side of a right triangle given hypotenuse and a side. No * - or other functions allowed
Find the remaining side of a triangle given the hypotenuse and a side. However, the normal functions and symbols are not allowe...

14 years ago

Solved

Joining Ranges
You are given a n-by-2 matrix. Each row represents a numeric range, e.g. x = [0 5; 10 3; 20 15; 16 19; 25 25] contains...

14 years ago

Solved

Combinations without using nchoosek
You have to generate a matrix with all possible combinations of n elements *taken 2* at a time, *without using nchoosek(1:n,2)* ...

14 years ago

Solved

Get the elements of diagonal and antidiagonal for any m-by-n matrix
In the problem <http://www.mathworks.com/matlabcentral/cody/problems/858-permute-diagonal-and-antidiagonal Problem 858. Permute ...

14 years ago

Solved

Cody Computer Part 5 - Guess the Name of Cody Computer
Network computers have generally a nickname to be identified. Can you guess the nickname of the Cody Computer? No inpu...

14 years ago

Solved

Sophie Germain prime
In number theory, a prime number p is a *Sophie Germain prime* if 2p + 1 is also prime. For example, 23 is a Sophie Germain prim...

14 years ago

Solved

Construct an index vector from two input vectors in vectorized fashion
Create an index vector defined by two input vectors, one defining the beginnings of one or more index ranges, and the other defi...

14 years ago

Solved

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 ...

14 years ago