From 4276edc6ef6bf1465158f6dfbce86b785cf74958 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Thu, 21 Dec 2017 13:55:55 +0100
Subject: [PATCH] Part 1 for day 21.

---
 2017/README.md              |   3 +-
 2017/day-21/input.txt       | 108 ++++++++++++++++++++++++++++++++++++
 2017/day-21/solution.coffee |  81 +++++++++++++++++++++++++++
 3 files changed, 191 insertions(+), 1 deletion(-)
 create mode 100644 2017/day-21/input.txt
 create mode 100644 2017/day-21/solution.coffee

diff --git a/2017/README.md b/2017/README.md
index 5701402..99e090e 100644
--- a/2017/README.md
+++ b/2017/README.md
@@ -12,7 +12,8 @@ The current plan, in no particular order:
 - [x] C++ - [Day 01](./day-01/solution.cpp)
 - [x] C# - [Day 07](./day-07/solution.cs)
 - [x] Clojure - [Day 03](./day-03/solution.clj)
-- [ ] Coffeescript
+- [ ] Coffeescript - [Day 21](./day-21/solution.coffee) (Need to finish
+  part 2)
 - [x] Go - [Day 13](./day-13/solution.go)
 - [x] Groovy - [Day 16](./day-16/solution.groovy)
 - [x] Haskell - [Day 15](./day-15/solution.hs)
diff --git a/2017/day-21/input.txt b/2017/day-21/input.txt
new file mode 100644
index 0000000..bda8318
--- /dev/null
+++ b/2017/day-21/input.txt
@@ -0,0 +1,108 @@
+../.. => .##/#../..#
+#./.. => .##/#../###
+##/.. => ..#/#.#/#..
+.#/#. => #../#../.#.
+##/#. => .#./#../#..
+##/## => .##/.../.##
+.../.../... => #.#./###./####/#..#
+#../.../... => .###/####/##../#.##
+.#./.../... => ###./.###/#..#/#.##
+##./.../... => ..../..../.#../##..
+#.#/.../... => ...#/.##./..../##..
+###/.../... => ##../##../##.#/..##
+.#./#../... => .#../###./##../####
+##./#../... => ####/##.#/..../..##
+..#/#../... => ..#./####/...#/#.##
+#.#/#../... => #.#./##../##../.##.
+.##/#../... => ##../####/..#./...#
+###/#../... => #..#/#.#./##.#/#.#.
+.../.#./... => .#.#/..#./#.../....
+#../.#./... => ##../..##/..##/.#..
+.#./.#./... => ..../##../##../#.##
+##./.#./... => ...#/##../#..#/.###
+#.#/.#./... => ####/##.#/###./..##
+###/.#./... => ..../...#/.###/.#..
+.#./##./... => #.#./#..#/.##./.#.#
+##./##./... => .###/#.../#..#/#.#.
+..#/##./... => .###/####/..../#.##
+#.#/##./... => ...#/.###/.###/.###
+.##/##./... => ..##/..##/.###/##.#
+###/##./... => ####/#..#/####/#.#.
+.../#.#/... => #.##/..#./.###/#.#.
+#../#.#/... => ####/##.#/##.#/....
+.#./#.#/... => #.../...#/#.##/#..#
+##./#.#/... => .#.#/##../##../....
+#.#/#.#/... => ##.#/#.../##../.#..
+###/#.#/... => ...#/###./.#.#/...#
+.../###/... => .###/#.##/#.../###.
+#../###/... => ..##/.#../.###/..#.
+.#./###/... => ..../.##./#.##/#.##
+##./###/... => .#.#/##.#/#.../#.#.
+#.#/###/... => ..#./#.../#.#./.##.
+###/###/... => ..##/.#.#/#..#/.##.
+..#/.../#.. => ..##/.#../##.#/##..
+#.#/.../#.. => ..#./..../#.../...#
+.##/.../#.. => .##./..##/####/#...
+###/.../#.. => #.##/..../##../#.##
+.##/#../#.. => .###/...#/###./....
+###/#../#.. => .#.#/#.#./#.##/..#.
+..#/.#./#.. => ...#/..#./..##/.#.#
+#.#/.#./#.. => #.../##.#/.###/#.#.
+.##/.#./#.. => ###./####/#..#/##.#
+###/.#./#.. => ..../..#./..../#...
+.##/##./#.. => .#.#/.##./.#.#/#.##
+###/##./#.. => ..../##../###./.#.#
+#../..#/#.. => ...#/#.../#.##/.###
+.#./..#/#.. => #..#/.#../###./#.#.
+##./..#/#.. => #.#./..#./###./###.
+#.#/..#/#.. => .#.#/##.#/##../####
+.##/..#/#.. => ###./..../.#../...#
+###/..#/#.. => #.#./.##./.#.#/#..#
+#../#.#/#.. => #.#./##.#/.#../.###
+.#./#.#/#.. => ##.#/#.#./#.../####
+##./#.#/#.. => .#.#/#.../..#./#.##
+..#/#.#/#.. => ##.#/.##./#.../.###
+#.#/#.#/#.. => ..##/..../..../####
+.##/#.#/#.. => ####/#.#./###./.#.#
+###/#.#/#.. => #.##/..#./##../#...
+#../.##/#.. => ..##/##.#/####/.#..
+.#./.##/#.. => ..##/##../.#../..##
+##./.##/#.. => ..##/.#.#/#..#/....
+#.#/.##/#.. => #.../##../...#/.#.#
+.##/.##/#.. => ##../...#/.###/.#.#
+###/.##/#.. => ####/..#./.##./#.##
+#../###/#.. => .#.#/##.#/#.#./#.#.
+.#./###/#.. => .###/#..#/.#.#/###.
+##./###/#.. => ##../.#../###./.#.#
+..#/###/#.. => #.##/..../...#/..#.
+#.#/###/#.. => #.../#..#/..../.#..
+.##/###/#.. => ####/#..#/..#./.#.#
+###/###/#.. => .##./##../.#../..#.
+.#./#.#/.#. => #.#./.###/#.#./..##
+##./#.#/.#. => .##./..../..##/##..
+#.#/#.#/.#. => ...#/..../.#.#/..##
+###/#.#/.#. => .#../####/#.#./#.##
+.#./###/.#. => #..#/.#.#/#..#/#.#.
+##./###/.#. => .#../##../#..#/..##
+#.#/###/.#. => #.#./.##./##.#/.#.#
+###/###/.#. => #.#./...#/..##/#...
+#.#/..#/##. => ..#./..#./...#/#..#
+###/..#/##. => #..#/###./..../##.#
+.##/#.#/##. => #.##/.#.#/...#/..##
+###/#.#/##. => #.##/...#/.##./.###
+#.#/.##/##. => ..../##.#/..../...#
+###/.##/##. => .###/#.../###./###.
+.##/###/##. => #.../#.#./.###/..#.
+###/###/##. => #.##/.#../..#./.#.#
+#.#/.../#.# => .##./##../###./.###
+###/.../#.# => ..##/...#/###./.#..
+###/#../#.# => ##.#/..#./#.##/.#..
+#.#/.#./#.# => .#../#.##/...#/###.
+###/.#./#.# => ..#./..../####/####
+###/##./#.# => ###./#..#/..../#..#
+#.#/#.#/#.# => ##.#/###./..../#...
+###/#.#/#.# => ##../.###/#..#/.#..
+#.#/###/#.# => #.../###./.###/..#.
+###/###/#.# => ..../.##./.#../###.
+###/#.#/### => ##../#.../.###/#...
+###/###/### => .###/###./#.##/..#.
diff --git a/2017/day-21/solution.coffee b/2017/day-21/solution.coffee
new file mode 100644
index 0000000..a1979cd
--- /dev/null
+++ b/2017/day-21/solution.coffee
@@ -0,0 +1,81 @@
+String.prototype.count = (pattern) ->
+	(this.match(pattern) || []).length
+
+stdin = process.openStdin()
+
+stdin.setEncoding 'utf8'
+
+data = ''
+
+stdin.on 'data', (input) ->
+	data += input
+
+stdin.on 'end', () ->
+	mappings = {}
+
+	rotate = (line) ->
+		rows = line.split '/'
+
+		newrows = []
+
+		len = rows.length
+
+		for i in [0...len]
+			newrows[i] = ''
+			for j in [0...len]
+				newrows[i] += rows[rows.length - 1 - j].substr i, 1
+
+		newrows.join '/'
+
+	flip = (line) ->
+		(row.split('').reverse().join '' for row in line.split '/').join '/'
+
+	view = (state) ->
+		console.log state.split('/').join "\n"
+
+	for line in data.trim().split('\n')
+		do (line) ->
+		[source, enhanced] = line.split ' => '
+
+		for i in [1..4]
+			mappings[source] = enhanced
+			mappings[flip source] = enhanced
+			source = rotate source
+
+	state = '.#./..#/###'
+	view state
+
+	for _ in [1..5]
+		newrows = []
+		oldrows = state.split '/'
+
+		if oldrows.length % 2 == 0
+			for i in [0...(oldrows.length / 2)]
+				currows = ['', '', '']
+
+				for j in [0...(oldrows.length / 2)]
+					curblock = (oldrows[2 * i].substr 2 * j, 2) + '/' + (oldrows[2 * i + 1].substr 2 * j, 2)
+					blockrows = mappings[curblock].split '/'
+
+					for r in [0..2]
+						currows[r] += blockrows[r]
+
+				for row in currows
+					newrows.push row
+		else
+			for i in [0...(oldrows.length / 3)]
+				currows = ['', '', '', '']
+
+				for j in [0...(oldrows.length / 3)]
+					curblock = (oldrows[3 * i].substr 3 * j, 3) + '/' + (oldrows[3 * i + 1].substr 3 * j, 3) + '/' + (oldrows[3 * i + 2].substr 3 * j, 3)
+					blockrows = mappings[curblock].split '/'
+
+					for r in [0..3]
+						currows[r] += blockrows[r]
+
+				for row in currows
+					newrows.push row
+
+		state = newrows.join '/'
+		console.log(state.count(/#/g))
+		view state