Update all exercises with upstream

exercises/practice/acronym/.docs/instructions.md

@@ -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   |

exercises/practice/acronym/.meta/tests.toml

@@ -29,3 +29,9 @@ description = "very long abbreviation"
 
 [6a078f49-c68d-4b7b-89af-33a1a98c28cc]
 description = "consecutive delimiters"
+
+[5118b4b1-4572-434c-8d57-5b762e57973e]
+description = "apostrophes"
+
+[adc12eab-ec2d-414f-b48c-66a4fc06cdef]
+description = "underscore emphasis"

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

@@ -4,9 +4,9 @@ Create an implementation of the affine cipher, an ancient encryption system crea
 
 The affine cipher is a type of monoalphabetic substitution cipher.
 Each character is mapped to its numeric equivalent, encrypted with a mathematical function and then converted to the letter relating to its new numeric value.
-Although all monoalphabetic ciphers are weak, the affine cipher is much stronger than the atbash cipher, because it has many more keys.
+Although all monoalphabetic ciphers are weak, the affine cipher is much stronger than the Atbash cipher, because it has many more keys.
 
-[//]: # ( monoalphabetic as spelled by Merriam-Webster, compare to polyalphabetic )
+[//]: # " monoalphabetic as spelled by Merriam-Webster, compare to polyalphabetic "
 
 ## Encryption
 
@@ -18,12 +18,12 @@ E(x) = (ai + b) mod m
 
 Where:
 
-- `i` is the letter's index from `0` to the length of the alphabet - 1
+- `i` is the letter's index from `0` to the length of the alphabet - 1.
 - `m` is the length of the alphabet.
   For the Roman alphabet `m` is `26`.
-- `a` and `b` are integers which make the encryption key
+- `a` and `b` are integers which make up the encryption key.
 
-Values `a` and `m` must be *coprime* (or, *relatively prime*) for automatic decryption to succeed, i.e., they have number `1` as their only common factor (more information can be found in the [Wikipedia article about coprime integers][coprime-integers]).
+Values `a` and `m` must be _coprime_ (or, _relatively prime_) for automatic decryption to succeed, i.e., they have number `1` as their only common factor (more information can be found in the [Wikipedia article about coprime integers][coprime-integers]).
 In case `a` is not coprime to `m`, your program should indicate that this is an error.
 Otherwise it should encrypt or decrypt with the provided key.
 

exercises/practice/allergies/.docs/instructions.md

@@ -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.

exercises/practice/alphametics/.docs/instructions.md

@@ -1,6 +1,6 @@
 # Instructions
 
-Write a function to solve alphametics puzzles.
+Given an alphametics puzzle, find the correct solution.
 
 [Alphametics][alphametics] is a puzzle where letters in words are replaced with numbers.
 
@@ -26,6 +26,4 @@ This is correct because every letter is replaced by a different number and the w
 
 Each letter must represent a different digit, and the leading digit of a multi-digit number must not be zero.
 
-Write a function to solve alphametics puzzles.
-
 [alphametics]: https://en.wikipedia.org/wiki/Alphametics

exercises/practice/alphametics/.meta/config.json

@@ -27,5 +27,5 @@
       ".meta/example.rb"
     ]
   },
-  "blurb": "Write a function to solve alphametics puzzles."
+  "blurb": "Given an alphametics puzzle, find the correct solution."
 }

exercises/practice/anagram/.meta/tests.toml

@@ -46,6 +46,11 @@ description = "detects anagrams using case-insensitive possible matches"
 
 [7cc195ad-e3c7-44ee-9fd2-d3c344806a2c]
 description = "does not detect an anagram if the original word is repeated"
+include = false
+
+[630abb71-a94e-4715-8395-179ec1df9f91]
+description = "does not detect an anagram if the original word is repeated"
+reimplements = "7cc195ad-e3c7-44ee-9fd2-d3c344806a2c"
 
 [9878a1c9-d6ea-4235-ae51-3ea2befd6842]
 description = "anagrams must use all letters exactly once"
@@ -73,3 +78,9 @@ include = false
 [33d3f67e-fbb9-49d3-a90e-0beb00861da7]
 description = "words other than themselves can be anagrams"
 reimplements = "a0705568-628c-4b55-9798-82e4acde51ca"
+
+[a6854f66-eec1-4afd-a137-62ef2870c051]
+description = "handles case of greek letters"
+
+[fd3509e5-e3ba-409d-ac3d-a9ac84d13296]
+description = "different characters may have the same bytes"

exercises/practice/armstrong-numbers/.docs/instructions.md

@@ -5,9 +5,9 @@ An [Armstrong number][armstrong-number] is a number that is the sum of its own d
 For example:
 
 - 9 is an Armstrong number, because `9 = 9^1 = 9`
-- 10 is *not* an Armstrong number, because `10 != 1^2 + 0^2 = 1`
+- 10 is _not_ an Armstrong number, because `10 != 1^2 + 0^2 = 1`
 - 153 is an Armstrong number, because: `153 = 1^3 + 5^3 + 3^3 = 1 + 125 + 27 = 153`
-- 154 is *not* an Armstrong number, because: `154 != 1^3 + 5^3 + 4^3 = 1 + 125 + 64 = 190`
+- 154 is _not_ an Armstrong number, because: `154 != 1^3 + 5^3 + 4^3 = 1 + 125 + 64 = 190`
 
 Write some code to determine whether a number is an Armstrong number.
 

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

@@ -24,7 +24,7 @@
       ".meta/example.rb"
     ]
   },
-  "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/bank-account/.docs/instructions.md

@@ -3,7 +3,7 @@
 Your task is to implement bank accounts supporting opening/closing, withdrawals, and deposits of money.
 
 As bank accounts can be accessed in many different ways (internet, mobile phones, automatic charges), your bank software must allow accounts to be safely accessed from multiple threads/processes (terminology depends on your programming language) in parallel.
-For example, there may be many deposits and withdrawals occurring in parallel; you need to ensure there is no [race conditions][wikipedia] between when you read the account balance and set the new balance.
+For example, there may be many deposits and withdrawals occurring in parallel; you need to ensure there are no [race conditions][wikipedia] between when you read the account balance and set the new balance.
 
 It should be possible to close an account; operations against a closed account must fail.
 

exercises/practice/binary-search-tree/.meta/config.json

@@ -28,6 +28,5 @@
     ]
   },
   "blurb": "Insert and search for numbers in a binary tree.",
-  "source": "Josh Cheek",
-  "source_url": "https://twitter.com/josh_cheek"
+  "source": "Josh Cheek"
 }

exercises/practice/binary-search/.docs/instructions.md

@@ -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.

exercises/practice/bob/.meta/tests.toml

@@ -71,6 +71,7 @@ description = "alternate silence"
 
 [66953780-165b-4e7e-8ce3-4bcb80b6385a]
 description = "multiple line question"
+include = false
 
 [5371ef75-d9ea-4103-bcfa-2da973ddec1b]
 description = "starting with whitespace"
@@ -83,3 +84,7 @@ description = "other whitespace"
 
 [12983553-8601-46a8-92fa-fcaa3bc4a2a0]
 description = "non-question ending with whitespace"
+
+[2c7278ac-f955-4eb4-bf8f-e33eb4116a15]
+description = "multiple line question"
+reimplements = "66953780-165b-4e7e-8ce3-4bcb80b6385a"

exercises/practice/book-store/.docs/instructions.md

@@ -12,9 +12,9 @@ If you buy 4 different books, you get a 20% discount.
 
 If you buy all 5, you get a 25% discount.
 
-Note: that if you buy four books, of which 3 are different titles, you get a 10% discount on the 3 that form part of a set, but the fourth book still costs $8.
+Note that if you buy four books, of which 3 are different titles, you get a 10% discount on the 3 that form part of a set, but the fourth book still costs $8.
 
-Your mission is to write a piece of code to calculate the price of any conceivable shopping basket (containing only books of the same series), giving as big a discount as possible.
+Your mission is to write code to calculate the price of any conceivable shopping basket (containing only books of the same series), giving as big a discount as possible.
 
 For example, how much does this basket of books cost?
 
@@ -26,36 +26,36 @@ For example, how much does this basket of books cost?
 
 One way of grouping these 8 books is:
 
-- 1 group of 5 --> 25% discount (1st,2nd,3rd,4th,5th)
-- +1 group of 3 --> 10% discount (1st,2nd,3rd)
+- 1 group of 5 (1st, 2nd,3rd, 4th, 5th)
+- 1 group of 3 (1st, 2nd, 3rd)
 
 This would give a total of:
 
 - 5 books at a 25% discount
-- +3 books at a 10% discount
+- 3 books at a 10% discount
 
 Resulting in:
 
-- 5 × (8 - 2.00) = 5 × 6.00 = $30.00
-- +3 × (8 - 0.80) = 3 × 7.20 = $21.60
+- 5 × (100% - 25%) × $8 = 5 × $6.00 = $30.00, plus
+- 3 × (100% - 10%) × $8 = 3 × $7.20 = $21.60
 
-For a total of $51.60
+Which equals $51.60.
 
 However, a different way to group these 8 books is:
 
-- 1 group of 4 books --> 20% discount  (1st,2nd,3rd,4th)
-- +1 group of 4 books --> 20% discount  (1st,2nd,3rd,5th)
+- 1 group of 4 books (1st, 2nd, 3rd, 4th)
+- 1 group of 4 books (1st, 2nd, 3rd, 5th)
 
 This would give a total of:
 
 - 4 books at a 20% discount
-- +4 books at a 20% discount
+- 4 books at a 20% discount
 
 Resulting in:
 
-- 4 × (8 - 1.60) = 4 × 6.40 = $25.60
-- +4 × (8 - 1.60) = 4 × 6.40 = $25.60
+- 4 × (100% - 20%) × $8 = 4 × $6.40 = $25.60, plus
+- 4 × (100% - 20%) × $8 = 4 × $6.40 = $25.60
 
-For a total of $51.20
+Which equals $51.20.
 
 And $51.20 is the price with the biggest discount.

exercises/practice/bowling/.docs/instructions.md

@@ -23,9 +23,9 @@ There are three cases for the tabulation of a frame.
 
 Here is a three frame example:
 
-| Frame 1         | Frame 2       | Frame 3                |
-| :-------------: |:-------------:| :---------------------:|
-| X (strike)      | 5/ (spare)    | 9 0 (open frame)       |
+|  Frame 1   |  Frame 2   |     Frame 3      |
+| :--------: | :--------: | :--------------: |
+| X (strike) | 5/ (spare) | 9 0 (open frame) |
 
 Frame 1 is (10 + 5 + 5) = 20
 

exercises/practice/change/.docs/instructions.md

@@ -1,14 +1,8 @@
 # Instructions
 
-Correctly determine the fewest number of coins to be given to a customer such that the sum of the coins' value would equal the correct amount of change.
+Determine the fewest number of coins to give a customer so that the sum of their values equals the correct amount of change.
 
-## For example
+## Examples
 
-- An input of 15 with [1, 5, 10, 25, 100] should return one nickel (5) and one dime (10) or [5, 10]
-- An input of 40 with [1, 5, 10, 25, 100] should return one nickel (5) and one dime (10) and one quarter (25) or [5, 10, 25]
-
-## Edge cases
-
-- Does your algorithm work for any given set of coins?
-- Can you ask for negative change?
-- Can you ask for a change value smaller than the smallest coin value?
+- An amount of 15 with available coin values [1, 5, 10, 25, 100] should return one coin of value 5 and one coin of value 10, or [5, 10].
+- An amount of 40 with available coin values [1, 5, 10, 25, 100] should return one coin of value 5, one coin of value 10, and one coin of value 25, or [5, 10, 25].

exercises/practice/change/.docs/introduction.md

@@ -0,0 +1,26 @@
+# Introduction
+
+In the mystical village of Coinholt, you stand behind the counter of your bakery, arranging a fresh batch of pastries.
+The door creaks open, and in walks Denara, a skilled merchant with a keen eye for quality goods.
+After a quick meal, she slides a shimmering coin across the counter, representing a value of 100 units.
+
+You smile, taking the coin, and glance at the total cost of the meal: 88 units.
+That means you need to return 12 units in change.
+
+Denara holds out her hand expectantly.
+"Just give me the fewest coins," she says with a smile.
+"My pouch is already full, and I don't want to risk losing them on the road."
+
+You know you have a few options.
+"We have Lumis (worth 10 units), Viras (worth 5 units), and Zenth (worth 2 units) available for change."
+
+You quickly calculate the possibilities in your head:
+
+- one Lumis (1 × 10 units) + one Zenth (1 × 2 units) = 2 coins total
+- two Viras (2 × 5 units) + one Zenth (1 × 2 units) = 3 coins total
+- six Zenth (6 × 2 units) = 6 coins total
+
+"The best choice is two coins: one Lumis and one Zenth," you say, handing her the change.
+
+Denara smiles, clearly impressed.
+"As always, you've got it right."

exercises/practice/change/.meta/tests.toml

@@ -33,6 +33,9 @@ description = "possible change without unit coins available"
 [9a166411-d35d-4f7f-a007-6724ac266178]
 description = "another possible change without unit coins available"
 
+[ce0f80d5-51c3-469d-818c-3e69dbd25f75]
+description = "a greedy approach is not optimal"
+
 [bbbcc154-e9e9-4209-a4db-dd6d81ec26bb]
 description = "no coins make 0 change"
 

exercises/practice/circular-buffer/.docs/instructions.md

@@ -4,39 +4,55 @@ A circular buffer, cyclic buffer or ring buffer is a data structure that uses a
 
 A circular buffer first starts empty and of some predefined length.
 For example, this is a 7-element buffer:
-<!-- prettier-ignore -->
-    [ ][ ][ ][ ][ ][ ][ ]
+
+```text
+[ ][ ][ ][ ][ ][ ][ ]
+```
 
 Assume that a 1 is written into the middle of the buffer (exact starting location does not matter in a circular buffer):
-<!-- prettier-ignore -->
-    [ ][ ][ ][1][ ][ ][ ]
+
+```text
+[ ][ ][ ][1][ ][ ][ ]
+```
 
 Then assume that two more elements are added — 2 & 3 — which get appended after the 1:
-<!-- prettier-ignore -->
-    [ ][ ][ ][1][2][3][ ]
+
+```text
+[ ][ ][ ][1][2][3][ ]
+```
 
 If two elements are then removed from the buffer, the oldest values inside the buffer are removed.
 The two elements removed, in this case, are 1 & 2, leaving the buffer with just a 3:
-<!-- prettier-ignore -->
-    [ ][ ][ ][ ][ ][3][ ]
+
+```text
+[ ][ ][ ][ ][ ][3][ ]
+```
 
 If the buffer has 7 elements then it is completely full:
-<!-- prettier-ignore -->
-    [5][6][7][8][9][3][4]
+
+```text
+[5][6][7][8][9][3][4]
+```
 
 When the buffer is full an error will be raised, alerting the client that further writes are blocked until a slot becomes free.
 
 When the buffer is full, the client can opt to overwrite the oldest data with a forced write.
 In this case, two more elements — A & B — are added and they overwrite the 3 & 4:
-<!-- prettier-ignore -->
-    [5][6][7][8][9][A][B]
+
+```text
+[5][6][7][8][9][A][B]
+```
 
 3 & 4 have been replaced by A & B making 5 now the oldest data in the buffer.
 Finally, if two elements are removed then what would be returned is 5 & 6 yielding the buffer:
-<!-- prettier-ignore -->
-    [ ][ ][7][8][9][A][B]
+
+```text
+[ ][ ][7][8][9][A][B]
+```
 
 Because there is space available, if the client again uses overwrite to store C & D then the space where 5 & 6 were stored previously will be used not the location of 7 & 8.
 7 is still the oldest element and the buffer is once again full.
-<!-- prettier-ignore -->
-    [C][D][7][8][9][A][B]
+
+```text
+[C][D][7][8][9][A][B]
+```

exercises/practice/clock/.meta/config.json

@@ -30,6 +30,5 @@
     ]
   },
   "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"
 }