21 questions linked to/from PPCG Jeopardy: Cops
65k views

### Is this number a prime?

Believe it or not, we do not yet have a code golf challenge for a simple primality test. While it may not be the most interesting challenge, particularly for "usual" languages, it can be nontrivial in ...
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### Draw the national flag of France

There have been many other flag challenges posted but not one for the national flag of France. This week seems like an appropriate time. Produce this flag in the fewest bytes possible: The image must ...
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### Count of "a"s and "b"s must be equal. Did you get it computer?

In the popular (and essential) computer science book, An Introduction to Formal Languages and Automata by Peter Linz, the following formal language is frequently stated: \large{L=\{a^n b^n:n\in\...
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### Convert YYYYMM to MMMYY

Basing on this SO question. Challenge is rather simple: given a date period in the format YYYYMM output it in the format MMMYY. ...
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### Source code ecological footprint

You've just been hired by a German car manufacturing company. Your first task, as an engineer, is to write a program that computes the ecological footprint of ASCII strings. The ecological footprint ...
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### Why was 6 afraid of 7?

Why was 6 afraid of 7? Because 7 8 9! Given a string apply the following transformations: If there is a 6 next to a 7 remove the 6 (6 is afraid of 7) If the sequence "789" appears remove the 8 and ...
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### I am passive aggressive and want to insult my boss without him finding out

It's been a rough few months at work and I feel like I just want to scream right to my boss' face. I am, however, not one to directly confront people I have a problem with. I also don't want to lose ...
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2k views

### Natural construction

The natural numbers including 0 are formally defined as sets, in the following way: Number 0 is defined as the empty set, {} For n ≥ 0, number n+1 is defined as n ∪ {n}. As a consequence, n = {0, 1, ...
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### Lever Simulator 2015

Why a Simulator? Kids these days don't have the time nor the ambition to actually go and stack boxes on the see-saw or play around with balancing physical objects. This leaves lots of room in the ...
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7k views

### Use xkcd's formula to approximate the world population

In xkcd 1047, Randall Munroe lists "slightly wrong" approximations of assorted quantities and numbers with varying precision and complexity, such as that the number of liters in a gallon is very close ...
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### Find the substring with the most 1's in a sequence

Introduction I want to find the substring with the most 1's in a sequence of 0's and 1's. ...
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### Primenary Strings

A Primenary (binary-prime) string is one which, when written as a binary grid, every row and column has a prime total. That's quite a vague explanation, so let's break it down with a worked example......
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### "Convenient palindrome" checker

If you've ever tried to write palindromic code before, you'd know how much brackets tend to get in your way. ()() is not a palindrome, even though it kinda looks ...
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### Keep the unique characters down

It's very simple: Your program or function should generate the following text: ...
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