88 lines
2.3 KiB
Markdown
88 lines
2.3 KiB
Markdown
# Crypto Square
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Implement the classic method for composing secret messages called a square code.
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The input is first normalized: The spaces and punctuation are removed
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from the English text and the message is downcased.
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Then, the normalized characters are broken into rows. These rows can be
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regarded as forming a rectangle when printed with intervening newlines.
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For example, the sentence
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> If man was meant to stay on the ground god would have given us roots
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is 54 characters long.
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Broken into 8-character columns, it yields 7 rows.
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Those 7 rows produce this rectangle when printed one per line:
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```plain
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ifmanwas
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meanttos
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tayonthe
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groundgo
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dwouldha
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vegivenu
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sroots
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```
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The coded message is obtained by reading down the columns going left to
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right.
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For example, the message above is coded as:
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```plain
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imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn sseoau
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```
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Write a program that, given an English text, outputs the encoded version
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of that text.
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The size of the square (number of columns) should be decided by the
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length of the message.
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If the message is a length that creates a perfect square (e.g. 4, 9, 16,
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25, 36, etc), use that number of columns.
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If the message doesn't fit neatly into a square, choose the number of
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columns that corresponds to the smallest square that is larger than the
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number of characters in the message.
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For example, a message 4 characters long should use a 2 x 2 square. A
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message that is 81 characters long would use a square that is 9 columns
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wide.
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A message between 5 and 8 characters long should use a rectangle 3
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characters wide.
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Output the encoded text grouped by column.
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For example:
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- "Have a nice day. Feed the dog & chill out!"
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- Normalizes to: "haveanicedayfeedthedogchillout"
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- Which has length: 30
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- And splits into 5 6-character rows:
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- "havean"
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- "iceday"
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- "feedth"
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- "edogch"
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- "illout"
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- Which yields a ciphertext beginning: "hifei acedl v…"
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To run the tests simply run the command `go test` in the exercise directory.
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If the test suite contains benchmarks, you can run these with the `-bench`
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flag:
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go test -bench .
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For more detailed info about the Go track see the [help
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page](http://help.exercism.io/getting-started-with-go.html).
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## Source
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J Dalbey's Programming Practice problems [view source](http://users.csc.calpoly.edu/~jdalbey/103/Projects/ProgrammingPractice.html)
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