Add day 6 solutions

4 files changed, 41 insertions, 0 deletions

diff --git a/2021/06/.gitignore b/2021/06/.gitignore
new file mode 100644
index 0000000..ffc46fe
--- /dev/null
+++ b/2021/06/.gitignore
@@ -0,0 +1 @@
+puzzle-[12].py
diff --git a/2021/06/Makefile b/2021/06/Makefile
new file mode 100644
index 0000000..9f2e236
--- /dev/null
+++ b/2021/06/Makefile
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+all:
+	m4 -D DAYS=80 puzzles.py | sed '/START PART 2/,/END PART 2/d' >puzzle-1.py
+	m4 -D DAYS=256 puzzles.py | sed '/START PART 1/,/END PART 1/d' >puzzle-2.py
+	chmod +x puzzle-[12].py
+
+.PHONY: clean
+clean:
+	rm -f puzzle-[12].py
diff --git a/2021/06/input b/2021/06/input
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index 0000000..229caa9
--- /dev/null
+++ b/2021/06/input
@@ -0,0 +1 @@
+1,2,1,1,1,1,1,1,2,1,3,1,1,1,1,3,1,1,1,5,1,1,1,4,5,1,1,1,3,4,1,1,1,1,1,1,1,5,1,4,1,1,1,1,1,1,1,5,1,3,1,3,1,1,1,5,1,1,1,1,1,5,4,1,2,4,4,1,1,1,1,1,5,1,1,1,1,1,5,4,3,1,1,1,1,1,1,1,5,1,3,1,4,1,1,3,1,1,1,1,1,1,2,1,4,1,3,1,1,1,1,1,5,1,1,1,2,1,1,1,1,2,1,1,1,1,4,1,3,1,1,1,1,1,1,1,1,5,1,1,4,1,1,1,1,1,3,1,3,3,1,1,1,2,1,1,1,1,1,1,1,1,1,5,1,1,1,1,5,1,1,1,1,2,1,1,1,4,1,1,1,2,3,1,1,1,1,1,1,1,1,2,1,1,1,2,3,1,2,1,1,5,4,1,1,2,1,1,1,3,1,4,1,1,1,1,3,1,2,5,1,1,1,5,1,1,1,1,1,4,1,1,4,1,1,1,2,2,2,2,4,3,1,1,3,1,1,1,1,1,1,2,2,1,1,4,2,1,4,1,1,1,1,1,5,1,1,4,2,1,1,2,5,4,2,1,1,1,1,4,2,3,5,2,1,5,1,3,1,1,5,1,1,4,5,1,1,1,1,4
diff --git a/2021/06/puzzles.py b/2021/06/puzzles.py
new file mode 100644
index 0000000..93dcfea
--- /dev/null
+++ b/2021/06/puzzles.py
@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+
+
+# This is not my original solution, that one involved numpy and some more ugly code, but after
+# seeing this solution I couldn't help but realize how obvious it was.
+
+
+import collections
+from typing import Counter
+
+
+def main() -> None:
+	with open("input", "r", encoding="utf-8") as f:
+		acc = collections.Counter(map(int, f.read().split(",")))
+
+	for _ in range(DAYS):
+		counts: Counter[int] = collections.Counter()
+		for a, c in acc.items():
+			if a:
+				counts[a - 1] += c
+			else:
+				counts[6] += c
+				counts[8] += c
+
+		acc = counts
+
+	print(sum(acc.values()))
+
+
+if __name__ == "__main__":
+	main()