From 563e354df57b8c45891ede5f094a88f9bf07ef3c Mon Sep 17 00:00:00 2001
From: Felix Van der Jeugt <felix.vanderjeugt@posteo.net>
Date: Mon, 6 Dec 2021 22:02:21 +0100
Subject: [PATCH] use deque in fish solution

---
 day06/part1.lua | 20 ++++++++++----------
 day06/part2.lua | 20 ++++++++++----------
 deque.lua       | 16 ++++++++++++++++
 prepare         |  1 +
 4 files changed, 37 insertions(+), 20 deletions(-)

diff --git a/day06/part1.lua b/day06/part1.lua
index 581a543..b9daba7 100644
--- a/day06/part1.lua
+++ b/day06/part1.lua
@@ -1,26 +1,26 @@
 #!/usr/bin/env luajit
 require("utils")
+require("deque")
 
-local fishes = {}
+local fishes = deque()
 for timer = 0, 9 do
-	fishes[timer] = 0
+	fishes:append(0)
 end
 
 for _, timer in pairs(split(io.open(arg[3]):read("*a"), ",")) do
-	fishes[tonumber(timer)] = fishes[tonumber(timer)] + 1
+	fishes:set(tonumber(timer), fishes:get(tonumber(timer)) + 1)
 end
 
 for day = 1, 80 do
-	fishes[9] = (fishes[0] or 0) + (fishes[9] or 0)
-	fishes[7] = (fishes[0] or 0) + (fishes[7] or 0)
-	for timer = 0, 9 do
-		fishes[timer] = fishes[timer + 1]
-	end
+	local breeding = fishes:popleft() or 0
+	fishes:append(0)
+	fishes:set(8, (fishes:get(8) or 0) + breeding)
+	fishes:set(6, (fishes:get(6) or 0) + breeding)
 end
 
 local sum = 0
-for timer, fishday in pairs(fishes) do
-	sum = sum + fishday
+while fishes.size > 0 do
+	sum = sum + (fishes:pop() or 0)
 end
 
 print(sum)
diff --git a/day06/part2.lua b/day06/part2.lua
index c0bad9c..ef1646e 100644
--- a/day06/part2.lua
+++ b/day06/part2.lua
@@ -1,26 +1,26 @@
 #!/usr/bin/env luajit
 require("utils")
+require("deque")
 
-local fishes = {}
+local fishes = deque()
 for timer = 0, 9 do
-	fishes[timer] = 0
+	fishes:append(0)
 end
 
 for _, timer in pairs(split(io.open(arg[3]):read("*a"), ",")) do
-	fishes[tonumber(timer)] = fishes[tonumber(timer)] + 1
+	fishes:set(tonumber(timer), fishes:get(tonumber(timer)) + 1)
 end
 
 for day = 1, 256 do
-	fishes[9] = (fishes[0] or 0) + (fishes[9] or 0)
-	fishes[7] = (fishes[0] or 0) + (fishes[7] or 0)
-	for timer = 0, 9 do
-		fishes[timer] = fishes[timer + 1]
-	end
+	local breeding = fishes:popleft() or 0
+	fishes:append(0)
+	fishes:set(8, (fishes:get(8) or 0) + breeding)
+	fishes:set(6, (fishes:get(6) or 0) + breeding)
 end
 
 local sum = 0
-for timer, fishday in pairs(fishes) do
-	sum = sum + fishday
+while fishes.size > 0 do
+	sum = sum + (fishes:pop() or 0)
 end
 
 print(sum)
diff --git a/deque.lua b/deque.lua
index 8d8a4c7..c2bbe29 100644
--- a/deque.lua
+++ b/deque.lua
@@ -14,6 +14,8 @@ function deque()
 		prepend = prepend,
 		append = append,
 		popleft = popleft,
+		get = get,
+		set = set,
 	}
 end
 
@@ -79,3 +81,17 @@ function popleft(self)
 		return nil
 	end
 end
+
+function get(self, i)
+	if 0 <= i and i < self.size then
+		return self.elems[(self.start + i) % self.cap]
+	else
+		return nil
+	end
+end
+
+function set(self, i, n)
+	if 0 <= i and i < self.size then
+		self.elems[(self.start + i) % self.cap] = n
+	end
+end
diff --git a/prepare b/prepare
index 821c878..968aff7 100755
--- a/prepare
+++ b/prepare
@@ -7,6 +7,7 @@ day="$(printf '%02d' "$day")"
 if test -f "day${day}/part${part}.lua"; then
 	/usr/bin/env luajit -v >/dev/null
 	cp "day${day}/part${part}.lua" run
+	chmod u+x run
 elif test -f "day${day}/part${part}.hs"; then
 	#stack build
 	stack ghc -- -O3 "day${day}/part${part}.hs" -o run