32 total contributions since 2013

Professional Interests: bioinformatics, data mining

Solved

Return the 3n+1 sequence for n

A Collatz sequence is the sequence where, for a given number n, the next number in the sequence is either n/2 if the number is e...

3 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...

3 years ago

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Remove the vowels

Remove all the vowels in the given phrase. Example: Input s1 = 'Jack and Jill went up the hill' Output s2 is 'Jck nd Jll wn...

3 years ago

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Finding Perfect Squares

Given a vector of numbers, return true if one of the numbers is a square of one of the other numbers. Otherwise return false. E...

3 years ago

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Weighted average

Given two lists of numbers, determine the weighted average. Example [1 2 3] and [10 15 20] should result in 33.333...

3 years ago

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Alphabetize by last name

Given a list of names in a cell array, sort the list by the last name. So if list = {'Barney Google','Snuffy Smith','Dagwood ...

4 years ago

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Fibonacci sequence

Calculate the nth Fibonacci number. Given n, return f where f = fib(n) and f(1) = 1, f(2) = 1, f(3) = 2, ... Examples: Inpu...

4 years ago

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Most nonzero elements in row

Given the matrix a, return the index r of the row with the most nonzero elements. Assume there will always be exactly one row th...

4 years ago

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Swap the first and last columns

Flip the outermost columns of matrix A, so that the first column becomes the last and the last column becomes the first. All oth...

4 years ago

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Find the two most distant points

Given a collection of points, return the indices of the rows that contain the two points most distant from one another. The inpu...

4 years ago

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Find all elements less than 0 or greater than 10 and replace them with NaN

Given an input vector x, find all elements of x less than 0 or greater than 10 and replace them with NaN. Example: Input ...

4 years ago

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Bullseye Matrix

Given n (always odd), return output a that has concentric rings of the numbers 1 through (n+1)/2 around the center point. Exampl...

4 years ago

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Find the numeric mean of the prime numbers in a matrix.

There will always be at least one prime in the matrix. Example: Input in = [ 8 3 5 9 ] Output out is 4...

4 years ago

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Making change

Given an amount of currency, return a vector of this form: [100 50 20 10 5 2 1 0.5 0.25 0.1 0.05 0.01] Example: Input a = ...

4 years ago

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Determine if input is odd

Given the input n, return true if n is odd or false if n is even.

4 years ago

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Remove any row in which a NaN appears

Given the matrix A, return B in which all the rows that have one or more <http://www.mathworks.com/help/techdoc/ref/nan.html NaN...

4 years ago

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Find the longest sequence of 1's in a binary sequence.

Given a string such as s = '011110010000000100010111' find the length of the longest string of consecutive 1's. In this examp...

4 years ago

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Column Removal

Remove the nth column from input matrix A and return the resulting matrix in output B. So if A = [1 2 3; 4 5 6]; and ...

4 years ago

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Cell joiner

You are given a cell array of strings and a string delimiter. You need to produce one string which is composed of each string fr...

4 years ago

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Find the sum of all the numbers of the input vector

Find the sum of all the numbers of the input vector x. Examples: Input x = [1 2 3 5] Output y is 11 Input x ...

4 years ago

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Summing digits

Given n, find the sum of the digits that make up 2^n. Example: Input n = 7 Output b = 11 since 2^7 = 128, and 1 + ...

4 years ago

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Who Has the Most Change?

You have a matrix for which each row is a person and the columns represent the number of quarters, nickels, dimes, and pennies t...

4 years ago

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Make the vector [1 2 3 4 5 6 7 8 9 10]

In MATLAB, you create a vector by enclosing the elements in square brackets like so: x = [1 2 3 4] Commas are optional, s...

4 years ago

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Detect a number and replace with two NaN's

Write code which replaces the number 1 with two NaNs. Example X = [ 1 2 NaN 4 1 3 7 NaN 1 4 NaN 2] ...

4 years ago

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Create times-tables

At one time or another, we all had to memorize boring times tables. 5 times 5 is 25. 5 times 6 is 30. 12 times 12 is way more th...

4 years ago

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Determine whether a vector is monotonically increasing

Return true if the elements of the input vector increase monotonically (i.e. each element is larger than the previous). Return f...

4 years ago

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Triangle Numbers

Triangle numbers are the sums of successive integers. So 6 is a triangle number because 6 = 1 + 2 + 3 which can be displa...

4 years ago

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Select every other element of a vector

Write a function which returns every other element of the vector passed in. That is, it returns the all odd-numbered elements, s...

4 years ago