Initial Commit

go/crypto-square/README.md

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

go/crypto-square/crypto_square.go

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+package cryptosquare
+
+import (
+	"math"
+	"regexp"
+	"strings"
+)
+
+// TestVersion is an exercism thing
+const TestVersion = 1
+
+// Encode implements the classic method for composing
+// secret messages called a square code
+func Encode(txt string) string {
+	r := regexp.MustCompile("[^a-zA-Z0-9]+")
+	nrm := strings.ToLower(r.ReplaceAllString(txt, ""))
+	// The string should be normalized now (alphanumeric, lower case)
+	sqrt := int(math.Ceil(math.Sqrt(float64(len(nrm)))))
+	var square, ret []string
+	var tmp string
+
+	// Build the initial square
+	for i := 0; i < len(nrm); i++ {
+		if i%sqrt == 0 && len(tmp) != 0 {
+			square = append(square, tmp)
+			tmp = ""
+		}
+		tmp += string(nrm[i])
+	}
+	square = append(square, tmp)
+	tmp = ""
+
+	// Now rebuild the string by columns
+	for i := 0; i < len(square[0]); i++ {
+		for j := 0; j < len(square); j++ {
+			if i < len(square[j]) {
+				tmp += string(square[j][i])
+			}
+		}
+		ret = append(ret, tmp)
+		tmp = ""
+	}
+
+	return strings.Join(ret, " ")
+}

go/crypto-square/crypto_square_test.go

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+package cryptosquare
+
+import "testing"
+
+const testVersion = 1
+
+// Retired testVersions
+// (none) 71ad8ac57fe7d5b777cfa1afd116cd41e1af55ed
+
+var tests = []struct {
+	pt string // plain text
+	ct string // cipher text
+}{
+	{
+		"s#$%^&plunk",
+		"su pn lk",
+	},
+	{
+		"1, 2, 3 GO!",
+		"1g 2o 3",
+	},
+	{
+		"1234",
+		"13 24",
+	},
+	{
+		"123456789",
+		"147 258 369",
+	},
+	{
+		"123456789abc",
+		"159 26a 37b 48c",
+	},
+	{
+		"Never vex thine heart with idle woes",
+		"neewl exhie vtetw ehaho ririe vntds",
+	},
+	{
+		"ZOMG! ZOMBIES!!!",
+		"zzi ooe mms gb",
+	},
+	{
+		"Time is an illusion. Lunchtime doubly so.",
+		"tasney inicds miohoo elntu illib suuml",
+	},
+	{
+		"We all know interspecies romance is weird.",
+		"wneiaw eorene awssci liprer lneoid ktcms",
+	},
+	{
+		"Madness, and then illumination.",
+		"msemo aanin dnin ndla etlt shui",
+	},
+	{
+		"Vampires are people too!",
+		"vrel aepe mset paoo irpo",
+	},
+	{
+		"",
+		"",
+	},
+	{
+		"1",
+		"1",
+	},
+	{
+		"12",
+		"1 2",
+	},
+	{
+		"12 3",
+		"13 2",
+	},
+	{
+		"12345678",
+		"147 258 36",
+	},
+	{
+		"123456789a",
+		"159 26a 37 48",
+	},
+	{
+		"If man was meant to stay on the ground god would have given us roots",
+		"imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn sseoau",
+	},
+	{
+		"Have a nice day. Feed the dog & chill out!",
+		"hifei acedl veeol eddgo aatcu nyhht",
+	},
+}
+
+func TestEncode(t *testing.T) {
+	if TestVersion != testVersion {
+		t.Errorf("Found TestVersion = %v, want %v.", TestVersion, testVersion)
+	}
+	for _, test := range tests {
+		if ct := Encode(test.pt); ct != test.ct {
+			t.Fatalf(`Encode(%q):
+got  %q
+want %q`, test.pt, ct, test.ct)
+		}
+	}
+}
+
+func BenchmarkEncode(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, test := range tests {
+			Encode(test.pt)
+		}
+	}
+}