diff --git a/exercises/practice/collatz-conjecture/.docs/instructions.md b/exercises/practice/collatz-conjecture/.docs/instructions.md index ba060483..af332a81 100644 --- a/exercises/practice/collatz-conjecture/.docs/instructions.md +++ b/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. diff --git a/exercises/practice/collatz-conjecture/.docs/introduction.md b/exercises/practice/collatz-conjecture/.docs/introduction.md new file mode 100644 index 00000000..c35bdeb6 --- /dev/null +++ b/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/ diff --git a/exercises/practice/collatz-conjecture/.meta/config.json b/exercises/practice/collatz-conjecture/.meta/config.json index 3e14a9ae..4bb55550 100644 --- a/exercises/practice/collatz-conjecture/.meta/config.json +++ b/exercises/practice/collatz-conjecture/.meta/config.json @@ -14,6 +14,6 @@ ] }, "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" } diff --git a/exercises/practice/grains/.meta/config.json b/exercises/practice/grains/.meta/config.json index ca1cbd17..f1b95863 100644 --- a/exercises/practice/grains/.meta/config.json +++ b/exercises/practice/grains/.meta/config.json @@ -15,5 +15,5 @@ }, "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" } diff --git a/exercises/practice/hamming/.docs/instructions.md b/exercises/practice/hamming/.docs/instructions.md index b9ae6efc..8f47a179 100644 --- a/exercises/practice/hamming/.docs/instructions.md +++ b/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. diff --git a/exercises/practice/hamming/.docs/introduction.md b/exercises/practice/hamming/.docs/introduction.md new file mode 100644 index 00000000..8419bf47 --- /dev/null +++ b/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 :) diff --git a/exercises/practice/leap/.meta/config.json b/exercises/practice/leap/.meta/config.json index 251fc126..72c90179 100644 --- a/exercises/practice/leap/.meta/config.json +++ b/exercises/practice/leap/.meta/config.json @@ -15,5 +15,5 @@ }, "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" } diff --git a/exercises/practice/luhn/.docs/instructions.md b/exercises/practice/luhn/.docs/instructions.md index 49934c10..5bbf007b 100644 --- a/exercises/practice/luhn/.docs/instructions.md +++ b/exercises/practice/luhn/.docs/instructions.md @@ -1,12 +1,10 @@ # Instructions -Given a number determine whether or not it is valid per the Luhn formula. +Determine whether a credit card 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. diff --git a/exercises/practice/luhn/.docs/introduction.md b/exercises/practice/luhn/.docs/introduction.md new file mode 100644 index 00000000..ec2bd709 --- /dev/null +++ b/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 ensure these numbers are valid and error-free. + +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 errors or fraud, such as incorrect transactions or unauthorized access. + +Can you ensure this is done right? The integrity of many services depends on you. diff --git a/exercises/practice/protein-translation/.docs/instructions.md b/exercises/practice/protein-translation/.docs/instructions.md index 7dc34d2e..44880802 100644 --- a/exercises/practice/protein-translation/.docs/instructions.md +++ b/exercises/practice/protein-translation/.docs/instructions.md @@ -2,12 +2,12 @@ Translate RNA sequences into proteins. -RNA can be broken into three nucleotide sequences called codons, and then translated to a polypeptide like so: +RNA can be broken into three-nucleotide sequences called codons, and then translated to a protein like so: RNA: `"AUGUUUUCU"` => translates to Codons: `"AUG", "UUU", "UCU"` -=> which become a polypeptide with the following sequence => +=> which become a protein with the following sequence => Protein: `"Methionine", "Phenylalanine", "Serine"` @@ -27,9 +27,9 @@ Protein: `"Methionine", "Phenylalanine", "Serine"` Note the stop codon `"UAA"` terminates the translation and the final methionine is not translated into the protein sequence. -Below are the codons and resulting Amino Acids needed for the exercise. +Below are the codons and resulting amino acids needed for the exercise. -| Codon | Protein | +| Codon | Amino Acid | | :----------------- | :------------ | | AUG | Methionine | | UUU, UUC | Phenylalanine | diff --git a/exercises/practice/rna-transcription/.meta/config.json b/exercises/practice/rna-transcription/.meta/config.json index a390ff71..4d813f3e 100644 --- a/exercises/practice/rna-transcription/.meta/config.json +++ b/exercises/practice/rna-transcription/.meta/config.json @@ -18,7 +18,7 @@ ".meta/example.f90" ] }, - "blurb": "Given a DNA strand, return its RNA Complement Transcription.", + "blurb": "Given a DNA strand, return its RNA complement.", "source": "Hyperphysics", "source_url": "https://web.archive.org/web/20220408112140/http://hyperphysics.phy-astr.gsu.edu/hbase/Organic/transcription.html" }