Khoi

Penn State University

Last seen: 3 days ago | Active since 2026

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Sum the Infinite Series
Given that 0 < x and x < 2*pi where x is in radians, write a function [c,s] = infinite_series(x); that returns with the...

4 days ago

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Golomb's self-describing sequence (based on Euler 341)
The Golomb's self-describing sequence {G(n)} is the only nondecreasing sequence of natural numbers such that n appears exactly G...

4 days ago

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Square Digits Number Chain Terminal Value (Inspired by Project Euler Problem 92)
Given a number _n_, return the terminal value of the number chain formed by summing the square of the digits. According to the P...

4 days ago

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"Look and say" sequence
What's the next number in this sequence? * [0] * [1 0] * [1 1 1 0] * [3 1 1 0] * [1 3 2 1 1 0] This a variant on the w...

4 days ago

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Alternating sum
Given vector x, calculate the alternating sum y = x(1) - x(2) + x(3) - x(4) + ...

4 days ago

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Natural numbers in string form
Create a cell array of strings containing the first n natural numbers. Slightly harder than it seems like it should be. Exampl...

4 days ago

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Fix the last element of a cell array
Note: this is lifted directly from <http://www.mathworks.com/matlabcentral/answers/82825-puzzler-for-a-monday Puzzler for a Mond...

4 days ago

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String Array Basics, Part 1: Convert Cell Array to String Array; No Missing Values
<http://www.mathworks.com/help/matlab/characters-and-strings.html String array> and cell array are two types of containers for s...

4 days ago

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Cell Counting: How Many Draws?
You are given a cell array containing information about a number of soccer games. Each cell contains one of the following: * ...

4 days ago

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Remove element(s) from cell array
You can easily remove an element (or a column in any dimension) from a normal matrix, but assigning that value (or range) empty....

4 days ago

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Convert a Cell Array into an Array
Given a square cell array: x = {'01', '56'; '234', '789'}; return a single character array: y = '0123456789'

4 days ago

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Split a string into chunks of specified length
Given a string and a vector of integers, break the string into chunks whose lengths are given by the elements of the vector. Ex...

4 days ago

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Convert a numerical matrix into a cell array of strings
Given a numerical matrix, output a *cell array of string*. For example: if input = 1:3 output is {'1','2','3'} whic...

4 days ago

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Create a cell array out of a struct
Create a cell array out of a (single) struct with the fieldname in the first column and the value in the second column: in: ...

4 days ago

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Find the stride of the longest skip sequence
We define a _skip sequence_ as a regularly-spaced list of integers such as might be generated by MATLAB's <http://www.mathworks....

4 days ago

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Project Euler: Problem 6, Natural numbers, squares and sums.
The sum of the squares of the first ten natural numbers is, 1^2 + 2^2 + ... + 10^2 = 385 The square of the sum of the first ...

4 days ago

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Sum of first n terms of a harmonic progression
Given inputs a, d and n, return the sum of the first n terms of the harmonic progression a, a/(1+d), a/(1+2d), a/(1+3d),....

4 days ago

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Integer sequence - 2 : Kolakoski sequence
Get the n-th term of Kolakoski Sequence.

4 days ago

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Sum all integers from 1 to 2^n
Given the number x, y must be the summation of all integers from 1 to 2^x. For instance if x=2 then y must be 1+2+3+4=10.

4 days ago

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Magic is simple (for beginners)
Determine for a magic square of order n, the magic sum m. For example m=15 for a magic square of order 3.

4 days ago

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Make a random, non-repeating vector.
This is a basic MATLAB operation. It is for instructional purposes. --- If you want to get a random permutation of integer...

4 days ago

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Number of 1s in a binary string
Find the number of 1s in the given binary string. Example. If the input string is '1100101', the output is 4. If the input stri...

4 days ago

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Return the first and last characters of a character array
Return the first and last character of a string, concatenated together. If there is only one character in the string, the functi...

4 days 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 days 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 find the logical indices o...

4 days 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 days ago

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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 = [1,2,3]; Returns 1.

4 days 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 days ago

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Swap the input arguments
Write a two-input, two-output function that swaps its two input arguments. For example: [q,r] = swap(5,10) returns q = ...

4 days 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]; ...

4 days ago