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Alexandra Rubio


Last seen: 4 meses ago
42 total contributions since 2020

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Prime factor digits
Consider the following number system. Calculate the prime factorization for each number n, then represent the prime factors in a...

5 meses ago

Solved


Pascal's Triangle
Given an integer n >= 0, generate the length n+1 row vector representing the n-th row of <http://en.wikipedia.org/wiki/Pascals_t...

5 meses ago

Solved


Subset Sum
Given a vector v of integers and an integer n, return the the indices of v (as a row vector in ascending order) that sum to n. I...

5 meses ago

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Return the largest number that is adjacent to a zero
This example comes from Steve Eddins' blog: <http://blogs.mathworks.com/steve/2009/05/27/learning-lessons-from-a-one-liner/ Lear...

5 meses ago

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...

5 meses ago

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Kaprekar Steps
6174 is the <http://en.wikipedia.org/wiki/6174_%28number%29 Kaprekar constant>. All natural numbers less than 10,000 (except som...

5 meses ago

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Return a list sorted by number of occurrences
Given a vector x, return a vector y of the unique values in x sorted by the number of occurrences in x. Ties are resolved by a ...

5 meses ago

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Getting logical indexes
This is a basic MATLAB operation. It is for instructional purposes. --- Logical indexing works like this. thresh = 4...

5 meses ago

Solved


Check if number exists in vector
Return 1 if number _a_ exists in vector _b_ otherwise return 0. a = 3; b = [1,2,4]; Returns 0. a = 3; b = [1,...

5 meses 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...

5 meses 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...

5 meses ago

Solved


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...

5 meses 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...

5 meses 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.

5 meses 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...

5 meses 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...

5 meses 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...

5 meses ago

Solved


Longest run of consecutive numbers (★★★★★)
(copy of Problem 672) Given a vector a, find the number(s) that is/are repeated consecutively most often. For example, if you...

6 meses ago

Solved


Generate a vector which contains a pyramid pattern (★★★★)
Generate a vector that contains terms that follows a pyramid pattern up to the nth row: 1 2 2 3 3 3 4 4 4 4 ...

6 meses ago

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Create a vector of n alternating ones and zeros (★★)
Given n, your output should be a vector y of numbers such that the first number is 1 and the numbers following it alternate betw...

6 meses ago

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Sum of elements of a vector (★★★)
Given any vector x = [x1, x2, x3, ... xn], compute the sum of its elements. Thus, if x = [ 1 3 -2 5 ], then the sum of its el...

6 meses ago

Solved


Magnitude of a vector (★★★)
Given a vector x with values [ x1, x2, x3, ..., xn ], compute the magnitude (or length) of the vector which is given by <<htt...

6 meses ago

Solved


Average of corner elements of a matrix (★★)
(copy of prob 2235) Calculate the average of corner elements of a matrix. e.g. x=[1 2 3; 4 5 6; 7 8 9;] avg = (1+3+7+9)...

6 meses ago

Solved


Variance computation (★)
Given a vector x with several values, compute the variance, whose formula is given by: <<https://i.imgur.com/Wg95KBE.gif>> ...

6 meses ago

Solved


Median computation (★)
Given a vector of values, compute the median. The median is defined as the middle value in a set of *sorted* data. Thus, if ...

6 meses ago

Solved


Column Removal (★★★)
(copy of prob 7) Remove the nth column from input matrix A and return the resulting matrix in output B. So if A = [1 2...

6 meses ago

Solved


Triangle Numbers (★★)
(copy of problem 5) Triangle numbers are the sums of successive integers. So 6 is a triangle number because 6 = 1 + 2 + 3...

6 meses ago

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Make a checkerboard matrix (★★★★★)
(copy of Prob. 4) Given an integer n, make an n-by-n matrix made up of alternating ones and zeros as shown below. The a(1...

6 meses ago

Solved


Doubling elements in a vector (★★)
(copy of prob. 1024) Given the vector A, return B in which all numbers in A are doubling. So for: A = [ 1 5 8 ] t...

6 meses ago

Solved


Create times-tables (★★★)
(copy of prob 33) At one time or another, we all had to memorize boring times tables. 5 times 5 is 25. 5 times 6 is 30. 12 ti...

6 meses ago

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