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10 changes: 5 additions & 5 deletions exercises/practice/acronym/.docs/instructions.md
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Expand Up @@ -10,8 +10,8 @@ Punctuation is handled as follows: hyphens are word separators (like whitespace)

For example:

|Input|Output|
|-|-|
|As Soon As Possible|ASAP|
|Liquid-crystal display|LCD|
|Thank George It's Friday!|TGIF|
| Input | Output |
| ------------------------- | ------ |
| As Soon As Possible | ASAP |
| Liquid-crystal display | LCD |
| Thank George It's Friday! | TGIF |
2 changes: 1 addition & 1 deletion exercises/practice/allergies/.docs/instructions.md
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Expand Up @@ -22,6 +22,6 @@ Now, given just that score of 34, your program should be able to say:
- Whether Tom is allergic to any one of those allergens listed above.
- All the allergens Tom is allergic to.

Note: a given score may include allergens **not** listed above (i.e. allergens that score 256, 512, 1024, etc.).
Note: a given score may include allergens **not** listed above (i.e. allergens that score 256, 512, 1024, etc.).
Your program should ignore those components of the score.
For example, if the allergy score is 257, your program should only report the eggs (1) allergy.
11 changes: 5 additions & 6 deletions exercises/practice/anagram/.docs/instructions.md
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# 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"`.
2 changes: 1 addition & 1 deletion exercises/practice/atbash-cipher/.docs/instructions.md
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# 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.
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2 changes: 1 addition & 1 deletion exercises/practice/atbash-cipher/.meta/config.json
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Expand Up @@ -17,7 +17,7 @@
".meta/AtbashCipherExample.m"
]
},
"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"
}
2 changes: 1 addition & 1 deletion exercises/practice/binary-search/.docs/instructions.md
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Expand Up @@ -11,7 +11,7 @@ Binary search only works when a list has been sorted.

The algorithm looks like this:

- Find the middle element of a *sorted* list and compare it with the item we're looking for.
- Find the middle element of a _sorted_ list and compare it with the item we're looking for.
- If the middle element is our item, then we're done!
- If the middle element is greater than our item, we can eliminate that element and all the elements **after** it.
- If the middle element is less than our item, we can eliminate that element and all the elements **before** it.
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3 changes: 1 addition & 2 deletions exercises/practice/clock/.meta/config.json
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Expand Up @@ -17,6 +17,5 @@
]
},
"blurb": "Implement a clock that handles times without dates.",
"source": "Pairing session with Erin Drummond",
"source_url": "https://twitter.com/ebdrummond"
"source": "Pairing session with Erin Drummond"
}
28 changes: 1 addition & 27 deletions exercises/practice/collatz-conjecture/.docs/instructions.md
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# 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.
28 changes: 28 additions & 0 deletions exercises/practice/collatz-conjecture/.docs/introduction.md
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# 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/
4 changes: 2 additions & 2 deletions exercises/practice/collatz-conjecture/.meta/config.json
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Expand Up @@ -19,6 +19,6 @@
]
},
"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"
}
4 changes: 2 additions & 2 deletions exercises/practice/etl/.meta/config.json
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Expand Up @@ -18,7 +18,7 @@
".meta/EtlExample.m"
]
},
"blurb": "We are going to do the `Transform` step of an Extract-Transform-Load.",
"source": "Exercise by the JumpstartLab team for students at The Turing School of Software and Design.",
"blurb": "Change the data format for scoring a game to more easily add other languages.",
"source": "Based on an exercise by the JumpstartLab team for students at The Turing School of Software and Design.",
"source_url": "https://turing.edu"
}
2 changes: 1 addition & 1 deletion exercises/practice/flatten-array/.docs/instructions.md
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Expand Up @@ -2,7 +2,7 @@

Take a nested list and return a single flattened list with all values except nil/null.

The challenge is to write a function that accepts an arbitrarily-deep nested list-like structure and returns a flattened structure without any nil/null values.
The challenge is to take an arbitrarily-deep nested list-like structure and produce a flattened structure without any nil/null values.

For example:

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20 changes: 10 additions & 10 deletions exercises/practice/grade-school/.docs/instructions.md
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# Instructions

Given students' names along with the grade that they are in, create a roster for the school.
Given students' names along with the grade they are in, create a roster for the school.

In the end, you should be able to:

- Add a student's name to the roster for a grade
- Add a student's name to the roster for a grade:
- "Add Jim to grade 2."
- "OK."
- Get a list of all students enrolled in a grade
- Get a list of all students enrolled in a grade:
- "Which students are in grade 2?"
- "We've only got Jim just now."
- "We've only got Jim right now."
- Get a sorted list of all students in all grades.
Grades should sort as 1, 2, 3, etc., and students within a grade should be sorted alphabetically by name.
- "Who all is enrolled in school right now?"
Grades should be sorted as 1, 2, 3, etc., and students within a grade should be sorted alphabetically by name.
- "Who is enrolled in school right now?"
- "Let me think.
We have Anna, Barb, and Charlie in grade 1, Alex, Peter, and Zoe in grade 2 and Jim in grade 5.
So the answer is: Anna, Barb, Charlie, Alex, Peter, Zoe and Jim"
We have Anna, Barb, and Charlie in grade 1, Alex, Peter, and Zoe in grade 2, and Jim in grade 5.
So the answer is: Anna, Barb, Charlie, Alex, Peter, Zoe, and Jim."

Note that all our students only have one name (It's a small town, what do you want?) and each student cannot be added more than once to a grade or the roster.
In fact, when a test attempts to add the same student more than once, your implementation should indicate that this is incorrect.
Note that all our students only have one name (it's a small town, what do you want?), and each student cannot be added more than once to a grade or the roster.
If a test attempts to add the same student more than once, your implementation should indicate that this is incorrect.
14 changes: 5 additions & 9 deletions exercises/practice/grains/.docs/instructions.md
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# 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
6 changes: 6 additions & 0 deletions exercises/practice/grains/.docs/introduction.md
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# 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.
2 changes: 1 addition & 1 deletion exercises/practice/grains/.meta/config.json
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Expand Up @@ -20,5 +20,5 @@
},
"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"
}
17 changes: 3 additions & 14 deletions exercises/practice/hamming/.docs/instructions.md
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# Instructions

Calculate the Hamming Distance between two DNA strands.
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.
We read DNA using the letters C, A, G and T.
Two strands might look like this:

GAGCCTACTAACGGGAT
CATCGTAATGACGGCCT
^ ^ ^ ^ ^ ^^

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 :)
They have 7 differences, and therefore the Hamming distance is 7.

## Implementation notes

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12 changes: 12 additions & 0 deletions exercises/practice/hamming/.docs/introduction.md
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# 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 :)
2 changes: 1 addition & 1 deletion exercises/practice/hamming/.meta/config.json
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Expand Up @@ -17,7 +17,7 @@
".meta/HammingExample.m"
]
},
"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/"
}
2 changes: 1 addition & 1 deletion exercises/practice/hello-world/.meta/config.json
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Expand Up @@ -20,7 +20,7 @@
".meta/HelloWorldExample.m"
]
},
"blurb": "The classical introductory exercise. Just say \"Hello, World!\".",
"blurb": "Exercism's classic introductory exercise. Just say \"Hello, World!\".",
"source": "This is an exercise to introduce users to using Exercism",
"source_url": "https://en.wikipedia.org/wiki/%22Hello,_world!%22_program"
}
2 changes: 1 addition & 1 deletion exercises/practice/isogram/.docs/instructions.md
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Expand Up @@ -11,4 +11,4 @@ Examples of isograms:
- downstream
- six-year-old

The word *isograms*, however, is not an isogram, because the s repeats.
The word _isograms_, however, is not an isogram, because the s repeats.
2 changes: 1 addition & 1 deletion exercises/practice/leap/.meta/config.json
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Expand Up @@ -19,5 +19,5 @@
},
"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"
}
11 changes: 5 additions & 6 deletions exercises/practice/luhn/.docs/instructions.md
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# 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.
Expand All @@ -22,7 +20,8 @@ The first step of the Luhn algorithm is to double every second digit, starting f
We will be doubling

```text
4_3_ 3_9_ 0_4_ 6_6_
4539 3195 0343 6467
↑ ↑ ↑ ↑ ↑ ↑ ↑ ↑ (double these)
```

If doubling the number results in a number greater than 9 then subtract 9 from the product.
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11 changes: 11 additions & 0 deletions exercises/practice/luhn/.docs/introduction.md
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# 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.
2 changes: 2 additions & 0 deletions exercises/practice/matching-brackets/.docs/instructions.md
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# Instructions

Given a string containing brackets `[]`, braces `{}`, parentheses `()`, or any combination thereof, verify that any and all pairs are matched and nested correctly.
Any other characters should be ignored.
For example, `"{what is (42)}?"` is balanced and `"[text}"` is not.
8 changes: 8 additions & 0 deletions exercises/practice/matching-brackets/.docs/introduction.md
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# Introduction

You're given the opportunity to write software for the Bracketeer™, an ancient but powerful mainframe.
The software that runs on it is written in a proprietary language.
Much of its syntax is familiar, but you notice _lots_ of brackets, braces and parentheses.
Despite the Bracketeer™ being powerful, it lacks flexibility.
If the source code has any unbalanced brackets, braces or parentheses, the Bracketeer™ crashes and must be rebooted.
To avoid such a scenario, you start writing code that can verify that brackets, braces, and parentheses are balanced before attempting to run it on the Bracketeer™.
2 changes: 1 addition & 1 deletion exercises/practice/pangram/.docs/instructions.md
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Expand Up @@ -5,4 +5,4 @@ Your task is to figure out if a sentence is a pangram.
A pangram is a sentence using every letter of the alphabet at least once.
It is case insensitive, so it doesn't matter if a letter is lower-case (e.g. `k`) or upper-case (e.g. `K`).

For this exercise we only use the basic letters used in the English alphabet: `a` to `z`.
For this exercise, a sentence is a pangram if it contains each of the 26 letters in the English alphabet.
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