In the hovertext of this xkcd: There's an "encoding" based on replacing runs of roman numerals with their sums. To do this: Find all runs of at least 1 roman numeral (IVXLCDM) Replace them with their sums, as numbers The Roman Numerals are IVXLCDM, corresponding respectively to 1, 5, 10, 50, 1...

The Fibonacci polynomials are a polynomial sequence defined as: \$F_0(x) = 0\$ \$F_1(x) = 1\$ \$F_n(x) = x F_{n-1}(x) + F_{n-2}(x)\$ The first few Fibonacci polynomials are: \$F_0(x) = 0\$ \$F_1(x) = 1\$ \$F_2(x) = x\$ \$F_3(x) = x^2 + 1\$ \$F_4(x) = x^3 + 2x\$ \$F_5(x) = x^4 + 3x^2 + 1\$ Whe...

For this challenge, a word is defined as a string of letters, separated by spaces. Given a string of words, and an integer i representing an index into that string, output the whole word which contains the character at index i. For example (using 0-based indexing), with the string code golf, and ...

In this challenge we considered a frog hopping around a lily pond. To recap the lily pond was represented as a finite list of positive integers. The frog can only jump forward or backwards by a distance equal to the number at its current location. So for example: [2, 3, 1, 4, 1] 🐸 Her...

It was reported on MSO that it is possible for a user to upvote or downvote more than once on a single post (resulting in reputation changes for the author for each vote). After some data examination, we were able to confirm that this vulnerability exists (it is happening due to race conditions s...

Word stays a word after taking away a letter This is a repost of this challenge Challenge There is an old, popular riddle: Find an English word with 8 letters that, taken away one letter, creates a new valid word. Repeat that until there are no letters left. Example solution: starting staring ...

Related Sometimes when I use my microwave, I do a little trolling and enter times such as 2:90 instead of 3:30 because they end up being the same time anyway. The microwave happily accepts this and starts counting down from 2:90, displaying times like 2:86 and 2:69 until it gets back to a stage ...

Change the Temperature of Swatchlings Warning: Contains Deltarune Chapter 2 Spoilers Summary Your challenge today is to determine the minimum number of turns needed to change the temperatures of an arbitrary amount of Swatchlings to all be the same. Context In the second chapter of Deltarune, the...

Hyphens with Interruptions This is a little unusual. You might have come upon simple programs that output a character repeatedly a number of times. This is the same, only with a little twist: interruptions! Your job is to write a program that receives a numeral input, then outputs without newl...

Write the shortest program or function that mimics the addition in this XKCD strip: Input Two positive decimal integers containing only the digits 150. Output The positive decimal integer result of adding the two inputs together in the manner shown above. This output should also only have the di...

Decipher a squashed series code-golf string parsing number Given a string containing a sequence of ascending consecutive positive integers, but with no separators (such as 7891011), output a list of the separated integers. For that example, the output should be [7, 8, 9, 10, 11]. To disambiguate ...

I X the source code, you Y the output! code-golf source-layout code-generation There's a zillion challenges of the form "I [do a thing to] the source code, you [do a thing to] the output!", like I double the source, you double the output! and I reverse the source code, you negate the output!. In...