13 questions linked to/from Tips for golfing in APL
12k views

### Create an “H” from smaller “H”s

Challenge Create a function or program that, when given an integer size, does the following: If size is equal to 1, output <...
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### An abundance of integers!

An Abundant number is any number where the sum of its proper divisors is greater than the original number. For example, the proper divisors of 12 are: ...
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### Let's golf a BIBABOBU decoder

While I was traveling in the future, I noticed a funny game among kids circa 2275. When they don't want their great-great-great-great-grand parents to understand what they're saying, they use the ...
3k views

### The max() is not enough

Intro A friend posed this question today in a slightly different way - "Can a single [Python] command determine the largest of some integers AND that they aren't equal?". While we didn't find a way ...
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### Rotation summation

Take a square matrix containing positive integers as input, and calculate the "rotated sum" of the matrix. Rotated sum: Take the sum of the original matrix and the same matrix rotated 90, 180 and ...
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### Sum square difference

The sum of the squares of the first ten natural numbers is, $1^2 + 2^2 + \dots + 10^2 = 385$ The square of the sum of the first ten natural numbers is, $(1 + 2 + ... + 10)^2 = 55^2 = 3025$ ...
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### Print the sequence

21, 21, 23, 20, 5, 25, 31, 24, ? Inspired by this Puzzle, given an integer $n>0$ , print out the following sequence until you reach a non-Integer (spoilered, in case you want to solve the puzzle ...
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### Alternating Pattern

In a now deleted stackoverflow question, someone posted the following: Write a program or function to print alternating patterns in * and ...
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### g​o​l​f​ ​a​t​a​n​2

Sometimes it really is a struggle to convert Cartesian coordinates (x,y) to Polar coordinates (r,phi). While you can calculate <...
894 views

### Running gene crossover algorithm

Your task is to accept as input two gene sequences, and a sequence of "cross over points", and return the gene sequence that results from the indicated cross overs. What I mean by this is, say you ...
916 views

### Area enclosed by perimeter loop

Find the area of a region of unit cells given its perimeter loop as a sequence of 90-degree turns. For example, take the three-cell region XX X whose perimeter ...