Sync docs and metadata (#604)

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* Sync additional docs and metadata

exercises/practice/accumulate/.docs/instructions.md

@@ -1,9 +1,6 @@
 # Instructions
 
-Implement the `accumulate` operation, which, given a collection and an
-operation to perform on each element of the collection, returns a new
-collection containing the result of applying that operation to each element of
-the input collection.
+Implement the `accumulate` operation, which, given a collection and an operation to perform on each element of the collection, returns a new collection containing the result of applying that operation to each element of the input collection.
 
 Given the collection of numbers:
 
@@ -21,6 +18,5 @@ Check out the test suite to see the expected function signature.
 
 ## Restrictions
 
-Keep your hands off that collect/map/fmap/whatchamacallit functionality
-provided by your standard library!
+Keep your hands off that collect/map/fmap/whatchamacallit functionality provided by your standard library!
 Solve this one yourself using other basic tools instead.

exercises/practice/accumulate/.meta/config.json

@@ -26,5 +26,5 @@
   },
   "blurb": "Implement the `accumulate` operation, which, given a collection and an operation to perform on each element of the collection, returns a new collection containing the result of applying that operation to each element of the input collection.",
   "source": "Conversation with James Edward Gray II",
-  "source_url": "https://twitter.com/jeg2"
+  "source_url": "http://graysoftinc.com/"
 }

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

@@ -4,5 +4,14 @@ Convert a phrase to its acronym.
 
 Techies love their TLA (Three Letter Acronyms)!
 
-Help generate some jargon by writing a program that converts a long name
-like Portable Network Graphics to its acronym (PNG).
+Help generate some jargon by writing a program that converts a long name like Portable Network Graphics to its acronym (PNG).
+
+Punctuation is handled as follows: hyphens are word separators (like whitespace); all other punctuation can be removed from the input.
+
+For example:
+
+| Input                     | Output |
+| ------------------------- | ------ |
+| As Soon As Possible       | ASAP   |
+| Liquid-crystal display    | LCD    |
+| Thank George It's Friday! | TGIF   |

exercises/practice/acronym/.meta/config.json

@@ -18,7 +18,7 @@
       ".meta/src/example.clj"
     ]
   },
-  "blurb": "Convert a long phrase to its acronym",
+  "blurb": "Convert a long phrase to its acronym.",
   "source": "Julien Vanier",
   "source_url": "https://github.com/monkbroc"
 }

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

@@ -2,10 +2,8 @@
 
 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.
+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.
 
 An Atbash cipher for the Latin alphabet would be as follows:
 
@@ -14,16 +12,16 @@ Plain:  abcdefghijklmnopqrstuvwxyz
 Cipher: zyxwvutsrqponmlkjihgfedcba
 ```
 
-It is a very weak cipher because it only has one possible key, and it is
-a simple monoalphabetic substitution cipher. However, this may not have
-been an issue in the cipher's time.
+It is a very weak cipher because it only has one possible key, and it is a simple mono-alphabetic substitution cipher.
+However, this may not have been an issue in the cipher's time.
 
-Ciphertext is written out in groups of fixed length, the traditional group size
-being 5 letters, and punctuation is excluded. This is to make it harder to guess
-things based on word boundaries.
+Ciphertext is written out in groups of fixed length, the traditional group size being 5 letters, leaving numbers unchanged, and punctuation is excluded.
+This is to make it harder to guess things based on word boundaries.
+All text will be encoded as lowercase letters.
 
 ## Examples
 
 - Encoding `test` gives `gvhg`
+- Encoding `x123 yes` gives `c123b vh`
 - Decoding `gvhg` gives `test`
 - Decoding `gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt` gives `thequickbrownfoxjumpsoverthelazydog`

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

@@ -25,5 +25,5 @@
   },
   "blurb": "Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.",
   "source": "Wikipedia",
-  "source_url": "http://en.wikipedia.org/wiki/Atbash"
+  "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/beer-song/.docs/instructions.md

@@ -305,17 +305,3 @@ Take it down and pass it around, no more bottles of beer on the wall.
 No more bottles of beer on the wall, no more bottles of beer.
 Go to the store and buy some more, 99 bottles of beer on the wall.
 ```
-
-## For bonus points
-
-Did you get the tests passing and the code clean? If you want to, these
-are some additional things you could try:
-
-* Remove as much duplication as you possibly can.
-* Optimize for readability, even if it means introducing duplication.
-* If you've removed all the duplication, do you have a lot of
-  conditionals? Try replacing the conditionals with polymorphism, if it
-  applies in this language. How readable is it?
-
-Then please share your thoughts in a comment on the submission. Did this
-experiment make the code better? Worse? Did you learn anything from it?

exercises/practice/beer-song/.meta/config.json

@@ -30,5 +30,5 @@
   },
   "blurb": "Produce the lyrics to that beloved classic, that field-trip favorite: 99 Bottles of Beer on the Wall.",
   "source": "Learn to Program by Chris Pine",
-  "source_url": "http://pine.fm/LearnToProgram/?Chapter=06"
+  "source_url": "https://pine.fm/LearnToProgram/?Chapter=06"
 }

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

@@ -2,29 +2,22 @@
 
 Insert and search for numbers in a binary tree.
 
-When we need to represent sorted data, an array does not make a good
-data structure.
-
-Say we have the array `[1, 3, 4, 5]`, and we add 2 to it so it becomes
-`[1, 3, 4, 5, 2]` now we must sort the entire array again! We can
-improve on this by realizing that we only need to make space for the new
-item `[1, nil, 3, 4, 5]`, and then adding the item in the space we
-added. But this still requires us to shift many elements down by one.
-
-Binary Search Trees, however, can operate on sorted data much more
-efficiently.
-
-A binary search tree consists of a series of connected nodes. Each node
-contains a piece of data (e.g. the number 3), a variable named `left`,
-and a variable named `right`. The `left` and `right` variables point at
-`nil`, or other nodes. Since these other nodes in turn have other nodes
-beneath them, we say that the left and right variables are pointing at
-subtrees. All data in the left subtree is less than or equal to the
-current node's data, and all data in the right subtree is greater than
-the current node's data.
-
-For example, if we had a node containing the data 4, and we added the
-data 2, our tree would look like this:
+When we need to represent sorted data, an array does not make a good data structure.
+
+Say we have the array `[1, 3, 4, 5]`, and we add 2 to it so it becomes `[1, 3, 4, 5, 2]`.
+Now we must sort the entire array again!
+We can improve on this by realizing that we only need to make space for the new item `[1, nil, 3, 4, 5]`, and then adding the item in the space we added.
+But this still requires us to shift many elements down by one.
+
+Binary Search Trees, however, can operate on sorted data much more efficiently.
+
+A binary search tree consists of a series of connected nodes.
+Each node contains a piece of data (e.g. the number 3), a variable named `left`, and a variable named `right`.
+The `left` and `right` variables point at `nil`, or other nodes.
+Since these other nodes in turn have other nodes beneath them, we say that the left and right variables are pointing at subtrees.
+All data in the left subtree is less than or equal to the current node's data, and all data in the right subtree is greater than the current node's data.
+
+For example, if we had a node containing the data 4, and we added the data 2, our tree would look like this:
 
       4
      /

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

@@ -24,6 +24,5 @@
     ]
   },
   "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/.docs/instructions.md

@@ -2,9 +2,9 @@
 
 Convert a binary number, represented as a string (e.g. '101010'), to its decimal equivalent using first principles.
 
-Implement binary to decimal conversion. Given a binary input
-string, your program should produce a decimal output. The
-program should handle invalid inputs.
+Implement binary to decimal conversion.
+Given a binary input string, your program should produce a decimal output.
+The program should handle invalid inputs.
 
 ## Note
 
@@ -15,13 +15,12 @@ program should handle invalid inputs.
 
 Decimal is a base-10 system.
 
-A number 23 in base 10 notation can be understood
-as a linear combination of powers of 10:
+A number 23 in base 10 notation can be understood as a linear combination of powers of 10:
 
 - The rightmost digit gets multiplied by 10^0 = 1
 - The next number gets multiplied by 10^1 = 10
 - ...
-- The *n*th number gets multiplied by 10^*(n-1)*.
+- The nth number gets multiplied by 10^_(n-1)_.
 - All these values are summed.
 
 So: `23 => 2*10^1 + 3*10^0 => 2*10 + 3*1 = 23 base 10`

exercises/practice/binary/.meta/config.json

@@ -24,7 +24,7 @@
       ".meta/src/example.clj"
     ]
   },
-  "blurb": "Convert a binary number, represented as a string (e.g. '101010'), to its decimal equivalent using first principles",
+  "blurb": "Convert a binary number, represented as a string (e.g. '101010'), to its decimal equivalent using first principles.",
   "source": "All of Computer Science",
-  "source_url": "http://www.wolframalpha.com/input/?i=binary&a=*C.binary-_*MathWorld-"
+  "source_url": "https://www.wolframalpha.com/examples/mathematics/numbers/base-conversions"
 }

exercises/practice/bob/.meta/config.json

@@ -34,5 +34,5 @@
   },
   "blurb": "Bob is a lackadaisical teenager. In conversation, his responses are very limited.",
   "source": "Inspired by the 'Deaf Grandma' exercise in Chris Pine's Learn to Program tutorial.",
-  "source_url": "http://pine.fm/LearnToProgram/?Chapter=06"
+  "source_url": "https://pine.fm/LearnToProgram/?Chapter=06"
 }

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

@@ -1,14 +1,11 @@
 # 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.
+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.
 
 ## For example
 
-- 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]
+- 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
 

exercises/practice/change/.meta/config.json

@@ -19,7 +19,7 @@
       ".meta/src/example.clj"
     ]
   },
-  "blurb": "Correctly determine change to be given using the least number of coins",
+  "blurb": "Correctly determine change to be given using the least number of coins.",
   "source": "Software Craftsmanship - Coin Change Kata",
   "source_url": "https://web.archive.org/web/20130115115225/http://craftsmanship.sv.cmu.edu:80/exercises/coin-change-kata"
 }

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

@@ -18,6 +18,5 @@
     ]
   },
   "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"
 }

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

@@ -2,10 +2,11 @@
 
 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.
+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.
 
@@ -24,4 +25,5 @@ Starting with n = 12, the steps would be as follows:
 8. 2
 9. 1
 
-Resulting in 9 steps. So for input n = 12, the return value would be 9.
+Resulting in 9 steps.
+So for input n = 12, the return value would be 9.

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

@@ -17,7 +17,7 @@
       ".meta/src/example.clj"
     ]
   },
-  "blurb": "Calculate the number of steps to reach 1 using the Collatz conjecture",
+  "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"
 }

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

@@ -24,6 +24,6 @@ Raising e to a complex exponent can be expressed as `e^(a + i * b) = e^a * e^(i
 Implement the following operations:
 
 - addition, subtraction, multiplication and division of two complex numbers,
-- conjugate, absolute value of a given complex number.
+- conjugate, absolute value, exponent of a given complex number.
 
 Assume the programming language you are using does not have an implementation of complex numbers.

exercises/practice/crypto-square/.docs/instructions.md

@@ -4,11 +4,10 @@ Implement the classic method for composing secret messages called a square code.
 
 Given an English text, output the encoded version of that text.
 
-First, the input is normalized: the spaces and punctuation are removed
-from the English text and the message is downcased.
+First, the input is normalized: the spaces and punctuation are removed from the English text and the message is down-cased.
 
-Then, the normalized characters are broken into rows.  These rows can be
-regarded as forming a rectangle when printed with intervening newlines.
+Then, the normalized characters are broken into rows.
+These rows can be regarded as forming a rectangle when printed with intervening newlines.
 
 For example, the sentence
 
@@ -22,13 +21,16 @@ is normalized to:
 "ifmanwasmeanttostayonthegroundgodwouldhavegivenusroots"
 ```
 
-The plaintext should be organized in to a rectangle.  The size of the
-rectangle (`r x c`) should be decided by the length of the message,
-such that `c >= r` and `c - r <= 1`, where `c` is the number of columns
-and `r` is the number of rows.
+The plaintext should be organized into a rectangle as square as possible.
+The size of the rectangle should be decided by the length of the message.
 
-Our normalized text is 54 characters long, dictating a rectangle with
-`c = 8` and `r = 7`:
+If `c` is the number of columns and `r` is the number of rows, then for the rectangle `r` x `c` find the smallest possible integer `c` such that:
+
+- `r * c >= length of message`,
+- and `c >= r`,
+- and `c - r <= 1`.
+
+Our normalized text is 54 characters long, dictating a rectangle with `c = 8` and `r = 7`:
 
 ```text
 "ifmanwas"
@@ -40,26 +42,22 @@ Our normalized text is 54 characters long, dictating a rectangle with
 "sroots  "
 ```
 
-The coded message is obtained by reading down the columns going left to
-right.
+The coded message is obtained by reading down the columns going left to right.
 
 The message above is coded as:
 
 ```text
 "imtgdvsfearwermayoogoanouuiontnnlvtwttddesaohghnsseoau"
 ```
 
-Output the encoded text in chunks that fill perfect rectangles `(r X c)`,
-with `c` chunks of `r` length, separated by spaces. For phrases that are
-`n` characters short of the perfect rectangle, pad each of the last `n`
-chunks with a single trailing space.
+Output the encoded text in chunks that fill perfect rectangles `(r X c)`, with `c` chunks of `r` length, separated by spaces.
+For phrases that are `n` characters short of the perfect rectangle, pad each of the last `n` chunks with a single trailing space.
 
 ```text
 "imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn  sseoau "
 ```
 
-Notice that were we to stack these, we could visually decode the
-ciphertext back in to the original message:
+Notice that were we to stack these, we could visually decode the ciphertext back in to the original message:
 
 ```text
 "imtgdvs"

exercises/practice/crypto-square/.meta/config.json

@@ -27,5 +27,5 @@
   },
   "blurb": "Implement the classic method for composing secret messages called a square code.",
   "source": "J Dalbey's Programming Practice problems",
-  "source_url": "http://users.csc.calpoly.edu/~jdalbey/103/Projects/ProgrammingPractice.html"
+  "source_url": "https://users.csc.calpoly.edu/~jdalbey/103/Projects/ProgrammingPractice.html"
 }