Sync upstream docs and metadata

exercises/practice/anagram/.docs/instructions.md

@@ -1,13 +1,12 @@
 # Instructions
 
-Your task is to, given a target word and a set of candidate words, to find the subset of the candidates that are anagrams of the target.
+Given a target word and one or more candidate words, your task is to find the candidates that are anagrams of the target.
 
 An anagram is a rearrangement of letters to form a new word: for example `"owns"` is an anagram of `"snow"`.
 A word is _not_ its own anagram: for example, `"stop"` is not an anagram of `"stop"`.
 
-The target and candidates are words of one or more ASCII alphabetic characters (`A`-`Z` and `a`-`z`).
-Lowercase and uppercase characters are equivalent: for example, `"PoTS"` is an anagram of `"sTOp"`, but `StoP` is not an anagram of `sTOp`.
-The anagram set is the subset of the candidate set that are anagrams of the target (in any order).
-Words in the anagram set should have the same letter case as in the candidate set.
+The target word and candidate words are made up of one or more ASCII alphabetic characters (`A`-`Z` and `a`-`z`).
+Lowercase and uppercase characters are equivalent: for example, `"PoTS"` is an anagram of `"sTOp"`, but `"StoP"` is not an anagram of `"sTOp"`.
+The words you need to find should be taken from the candidate words, using the same letter case.
 
-Given the target `"stone"` and candidates `"stone"`, `"tones"`, `"banana"`, `"tons"`, `"notes"`, `"Seton"`, the anagram set is `"tones"`, `"notes"`, `"Seton"`.
+Given the target `"stone"` and the candidate words `"stone"`, `"tones"`, `"banana"`, `"tons"`, `"notes"`, and `"Seton"`, the anagram words you need to find are `"tones"`, `"notes"`, and `"Seton"`.

exercises/practice/atbash-cipher/.docs/instructions.md

@@ -1,6 +1,6 @@
 # Instructions
 
-Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.
+Create an implementation of the Atbash cipher, an ancient encryption system created in the Middle East.
 
 The Atbash cipher is a simple substitution cipher that relies on transposing all the letters in the alphabet such that the resulting alphabet is backwards.
 The first letter is replaced with the last letter, the second with the second-last, and so on.

exercises/practice/atbash-cipher/.meta/config.json

@@ -14,7 +14,7 @@
       ".meta/atbash-cipher.ys"
     ]
   },
-  "blurb": "Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.",
+  "blurb": "Create an implementation of the Atbash cipher, an ancient encryption system created in the Middle East.",
   "source": "Wikipedia",
   "source_url": "https://en.wikipedia.org/wiki/Atbash"
 }

exercises/practice/collatz-conjecture/.docs/instructions.md

@@ -1,29 +1,3 @@
 # Instructions
 
-The Collatz Conjecture or 3x+1 problem can be summarized as follows:
-
-Take any positive integer n.
-If n is even, divide n by 2 to get n / 2.
-If n is odd, multiply n by 3 and add 1 to get 3n + 1.
-Repeat the process indefinitely.
-The conjecture states that no matter which number you start with, you will always reach 1 eventually.
-
-Given a number n, return the number of steps required to reach 1.
-
-## Examples
-
-Starting with n = 12, the steps would be as follows:
-
-0. 12
-1. 6
-2. 3
-3. 10
-4. 5
-5. 16
-6. 8
-7. 4
-8. 2
-9. 1
-
-Resulting in 9 steps.
-So for input n = 12, the return value would be 9.
+Given a positive integer, return the number of steps it takes to reach 1 according to the rules of the Collatz Conjecture.

exercises/practice/collatz-conjecture/.docs/introduction.md

@@ -0,0 +1,28 @@
+# Introduction
+
+One evening, you stumbled upon an old notebook filled with cryptic scribbles, as though someone had been obsessively chasing an idea.
+On one page, a single question stood out: **Can every number find its way to 1?**
+It was tied to something called the **Collatz Conjecture**, a puzzle that has baffled thinkers for decades.
+
+The rules were deceptively simple.
+Pick any positive integer.
+
+- If it's even, divide it by 2.
+- If it's odd, multiply it by 3 and add 1.
+
+Then, repeat these steps with the result, continuing indefinitely.
+
+Curious, you picked number 12 to test and began the journey:
+
+12 ➜ 6 ➜ 3 ➜ 10 ➜ 5 ➜ 16 ➜ 8 ➜ 4 ➜ 2 ➜ 1
+
+Counting from the second number (6), it took 9 steps to reach 1, and each time the rules repeated, the number kept changing.
+At first, the sequence seemed unpredictable — jumping up, down, and all over.
+Yet, the conjecture claims that no matter the starting number, we'll always end at 1.
+
+It was fascinating, but also puzzling.
+Why does this always seem to work?
+Could there be a number where the process breaks down, looping forever or escaping into infinity?
+The notebook suggested solving this could reveal something profound — and with it, fame, [fortune][collatz-prize], and a place in history awaits whoever could unlock its secrets.
+
+[collatz-prize]: https://mathprize.net/posts/collatz-conjecture/

exercises/practice/collatz-conjecture/.meta/config.json

@@ -17,6 +17,6 @@
     ]
   },
   "blurb": "Calculate the number of steps to reach 1 using the Collatz conjecture.",
-  "source": "An unsolved problem in mathematics named after mathematician Lothar Collatz",
-  "source_url": "https://en.wikipedia.org/wiki/3x_%2B_1_problem"
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Collatz_conjecture"
 }

exercises/practice/eliuds-eggs/.docs/introduction.md

@@ -12,36 +12,54 @@ The position information encoding is calculated as follows:
 2. Convert the number from binary to decimal.
 3. Show the result on the display.
 
-Example 1:
+## Example 1
+
+![Seven individual nest boxes arranged in a row whose first, third, fourth and seventh nests each have a single egg.](https://assets.exercism.org/images/exercises/eliuds-eggs/example-1-coop.svg)
 
 ```text
-Chicken Coop:
  _ _ _ _ _ _ _
 |E| |E|E| | |E|
+```
+
+### Resulting Binary
+
+![1011001](https://assets.exercism.org/images/exercises/eliuds-eggs/example-1-binary.svg)
+
+```text
+ _ _ _ _ _ _ _
+|1|0|1|1|0|0|1|
+```
 
-Resulting Binary:
- 1 0 1 1 0 0 1
+### Decimal number on the display
 
-Decimal number on the display:
 89
 
-Actual eggs in the coop:
+### Actual eggs in the coop
+
 4
+
+## Example 2
+
+![Seven individual nest boxes arranged in a row where only the fourth nest has an egg.](https://assets.exercism.org/images/exercises/eliuds-eggs/example-2-coop.svg)
+
+```text
+ _ _ _ _ _ _ _
+| | | |E| | | |
 ```
 
-Example 2:
+### Resulting Binary
+
+![0001000](https://assets.exercism.org/images/exercises/eliuds-eggs/example-2-binary.svg)
 
 ```text
-Chicken Coop:
- _ _ _ _ _ _ _ _
-| | | |E| | | | |
+ _ _ _ _ _ _ _
+|0|0|0|1|0|0|0|
+```
 
-Resulting Binary:
- 0 0 0 1 0 0 0 0
+### Decimal number on the display
 
-Decimal number on the display:
-16
+8
+
+### Actual eggs in the coop
 
-Actual eggs in the coop:
 1
-```

exercises/practice/grains/.docs/instructions.md

@@ -1,15 +1,11 @@
 # Instructions
 
-Calculate the number of grains of wheat on a chessboard given that the number on each square doubles.
+Calculate the number of grains of wheat on a chessboard.
 
-There once was a wise servant who saved the life of a prince.
-The king promised to pay whatever the servant could dream up.
-Knowing that the king loved chess, the servant told the king he would like to have grains of wheat.
-One grain on the first square of a chess board, with the number of grains doubling on each successive square.
+A chessboard has 64 squares.
+Square 1 has one grain, square 2 has two grains, square 3 has four grains, and so on, doubling each time.
 
-There are 64 squares on a chessboard (where square 1 has one grain, square 2 has two grains, and so on).
+Write code that calculates:
 
-Write code that shows:
-
-- how many grains were on a given square, and
+- the number of grains on a given square
 - the total number of grains on the chessboard

exercises/practice/grains/.docs/introduction.md

@@ -0,0 +1,6 @@
+# Introduction
+
+There once was a wise servant who saved the life of a prince.
+The king promised to pay whatever the servant could dream up.
+Knowing that the king loved chess, the servant told the king he would like to have grains of wheat.
+One grain on the first square of a chessboard, with the number of grains doubling on each successive square.

exercises/practice/grains/.meta/config.json

@@ -18,5 +18,5 @@
   },
   "blurb": "Calculate the number of grains of wheat on a chessboard given that the number on each square doubles.",
   "source": "The CodeRanch Cattle Drive, Assignment 6",
-  "source_url": "https://coderanch.com/wiki/718824/Grains"
+  "source_url": "https://web.archive.org/web/20240908084142/https://coderanch.com/wiki/718824/Grains"
 }

exercises/practice/hamming/.docs/instructions.md

@@ -2,15 +2,6 @@
 
 Calculate the Hamming distance between two DNA strands.
 
-Your body is made up of cells that contain DNA.
-Those cells regularly wear out and need replacing, which they achieve by dividing into daughter cells.
-In fact, the average human body experiences about 10 quadrillion cell divisions in a lifetime!
-
-When cells divide, their DNA replicates too.
-Sometimes during this process mistakes happen and single pieces of DNA get encoded with the incorrect information.
-If we compare two strands of DNA and count the differences between them we can see how many mistakes occurred.
-This is known as the "Hamming distance".
-
 We read DNA using the letters C, A, G and T.
 Two strands might look like this:
 
@@ -20,8 +11,6 @@ Two strands might look like this:
 
 They have 7 differences, and therefore the Hamming distance is 7.
 
-The Hamming distance is useful for lots of things in science, not just biology, so it's a nice phrase to be familiar with :)
-
 ## Implementation notes
 
 The Hamming distance is only defined for sequences of equal length, so an attempt to calculate it between sequences of different lengths should not work.

exercises/practice/hamming/.docs/introduction.md

@@ -0,0 +1,12 @@
+# Introduction
+
+Your body is made up of cells that contain DNA.
+Those cells regularly wear out and need replacing, which they achieve by dividing into daughter cells.
+In fact, the average human body experiences about 10 quadrillion cell divisions in a lifetime!
+
+When cells divide, their DNA replicates too.
+Sometimes during this process mistakes happen and single pieces of DNA get encoded with the incorrect information.
+If we compare two strands of DNA and count the differences between them, we can see how many mistakes occurred.
+This is known as the "Hamming distance".
+
+The Hamming distance is useful in many areas of science, not just biology, so it's a nice phrase to be familiar with :)

exercises/practice/hamming/.meta/config.json

@@ -14,7 +14,7 @@
       ".meta/hamming.ys"
     ]
   },
-  "blurb": "Calculate the Hamming difference between two DNA strands.",
+  "blurb": "Calculate the Hamming distance between two DNA strands.",
   "source": "The Calculating Point Mutations problem at Rosalind",
   "source_url": "https://rosalind.info/problems/hamm/"
 }

exercises/practice/leap/.meta/config.json

@@ -17,5 +17,5 @@
   },
   "blurb": "Determine whether a given year is a leap year.",
   "source": "CodeRanch Cattle Drive, Assignment 3",
-  "source_url": "https://coderanch.com/t/718816/Leap"
+  "source_url": "https://web.archive.org/web/20240907033714/https://coderanch.com/t/718816/Leap"
 }

exercises/practice/luhn/.docs/instructions.md

@@ -1,65 +1,68 @@
 # Instructions
 
-Given a number determine whether or not it is valid per the Luhn formula.
+Determine whether a number is valid according to the [Luhn formula][luhn].
 
-The [Luhn algorithm][luhn] is a simple checksum formula used to validate a variety of identification numbers, such as credit card numbers and Canadian Social Insurance Numbers.
+The number will be provided as a string.
 
-The task is to check if a given string is valid.
-
-## Validating a Number
+## Validating a number
 
 Strings of length 1 or less are not valid.
 Spaces are allowed in the input, but they should be stripped before checking.
 All other non-digit characters are disallowed.
 
-### Example 1: valid credit card number
+## Examples
 
-```text
-4539 3195 0343 6467
-```
+### Valid credit card number
 
-The first step of the Luhn algorithm is to double every second digit, starting from the right.
-We will be doubling
+The number to be checked is `4539 3195 0343 6467`.
+
+The first step of the Luhn algorithm is to start at the end of the number and double every second digit, beginning with the second digit from the right and moving left.
 
 ```text
 4539 3195 0343 6467
 ↑ ↑  ↑ ↑  ↑ ↑  ↑ ↑  (double these)
 ```
 
-If doubling the number results in a number greater than 9 then subtract 9 from the product.
-The results of our doubling:
+If the result of doubling a digit is greater than 9, we subtract 9 from that result.
+We end up with:
 
 ```text
 8569 6195 0383 3437
 ```
 
-Then sum all of the digits:
+Finally, we sum all digits.
+If the sum is evenly divisible by 10, the original number is valid.
 
 ```text
-8+5+6+9+6+1+9+5+0+3+8+3+3+4+3+7 = 80
+8 + 5 + 6 + 9 + 6 + 1 + 9 + 5 + 0 + 3 + 8 + 3 + 3 + 4 + 3 + 7 = 80
 ```
 
-If the sum is evenly divisible by 10, then the number is valid.
-This number is valid!
+80 is evenly divisible by 10, so number `4539 3195 0343 6467` is valid!
+
+### Invalid Canadian SIN
+
+The number to be checked is `066 123 468`.
 
-### Example 2: invalid credit card number
+We start at the end of the number and double every second digit, beginning with the second digit from the right and moving left.
 
 ```text
-8273 1232 7352 0569
+066 123 478
+ ↑  ↑ ↑  ↑  (double these)
 ```
 
-Double the second digits, starting from the right
+If the result of doubling a digit is greater than 9, we subtract 9 from that result.
+We end up with:
 
 ```text
-7253 2262 5312 0539
+036 226 458
 ```
 
-Sum the digits
+We sum the digits:
 
 ```text
-7+2+5+3+2+2+6+2+5+3+1+2+0+5+3+9 = 57
+0 + 3 + 6 + 2 + 2 + 6 + 4 + 5 + 8 = 36
 ```
 
-57 is not evenly divisible by 10, so this number is not valid.
+36 is not evenly divisible by 10, so number `066 123 478` is not valid!
 
 [luhn]: https://en.wikipedia.org/wiki/Luhn_algorithm

exercises/practice/luhn/.docs/introduction.md

@@ -0,0 +1,11 @@
+# Introduction
+
+At the Global Verification Authority, you've just been entrusted with a critical assignment.
+Across the city, from online purchases to secure logins, countless operations rely on the accuracy of numerical identifiers like credit card numbers, bank account numbers, transaction codes, and tracking IDs.
+The Luhn algorithm is a simple checksum formula used to help identify mistyped numbers.
+
+A batch of identifiers has just arrived on your desk.
+All of them must pass the Luhn test to ensure they're legitimate.
+If any fail, they'll be flagged as invalid, preventing mistakes such as incorrect transactions or failed account verifications.
+
+Can you ensure this is done right? The integrity of many services depends on you.

exercises/practice/pascals-triangle/.docs/introduction.md

@@ -13,7 +13,7 @@ Over the next hour, your teacher reveals some amazing things hidden in this tria
 - It contains the Fibonacci sequence.
 - If you color odd and even numbers differently, you get a beautiful pattern called the [Sierpiński triangle][wikipedia-sierpinski-triangle].
 
-The teacher implores you and your classmates to lookup other uses, and assures you that there are lots more!
+The teacher implores you and your classmates to look up other uses, and assures you that there are lots more!
 At that moment, the school bell rings.
 You realize that for the past hour, you were completely absorbed in learning about Pascal's triangle.
 You quickly grab your laptop from your bag and go outside, ready to enjoy both the sunshine _and_ the wonders of Pascal's triangle.

exercises/practice/phone-number/.docs/instructions.md

@@ -1,6 +1,6 @@
 # Instructions
 
-Clean up user-entered phone numbers so that they can be sent SMS messages.
+Clean up phone numbers so that they can be sent SMS messages.
 
 The **North American Numbering Plan (NANP)** is a telephone numbering system used by many countries in North America like the United States, Canada or Bermuda.
 All NANP-countries share the same international country code: `1`.

exercises/practice/phone-number/.docs/introduction.md

@@ -0,0 +1,12 @@
+# Introduction
+
+You've joined LinkLine, a leading communications company working to ensure reliable connections for everyone.
+The team faces a big challenge: users submit phone numbers in all sorts of formats — dashes, spaces, dots, parentheses, and even prefixes.
+Some numbers are valid, while others are impossible to use.
+
+Your mission is to turn this chaos into order.
+You'll clean up valid numbers, formatting them appropriately for use in the system.
+At the same time, you'll identify and filter out any invalid entries.
+
+The success of LinkLine's operations depends on your ability to separate the useful from the unusable.
+Are you ready to take on the challenge and keep the connections running smoothly?