3 files changed, 151 insertions, 0 deletions
diff --git a/2020/10/input b/2020/10/input
new file mode 100644
index 0000000..379b145
--- /dev/null
+++ b/2020/10/input
@@ -0,0 +1,108 @@
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diff --git a/2020/10/puzzle-1.sh b/2020/10/puzzle-1.sh
new file mode 100755
index 0000000..f31af02
--- /dev/null
+++ b/2020/10/puzzle-1.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env sh
+
+sort -n input | awk '
+BEGIN  { o = t = 1 }
+NR > 1 { if ($0 - prev == 1) o++; else if ($0 - prev == 3) t++; }
+       { prev = $0 }
+END    { print o * t }'
diff --git a/2020/10/puzzle-2.py b/2020/10/puzzle-2.py
new file mode 100755
index 0000000..bdf7bbf
--- /dev/null
+++ b/2020/10/puzzle-2.py
@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+
+from typing import List
+
+adaptors: list[str]
+
+
+def combos(i: int, counts: dict[int, dict[int, int]] = {}) -> int:
+	if i == len(adaptors) - 1:
+		return 1
+	if i in counts:
+		return counts[i]
+
+	ans = 0
+	for j in range(i + 1, len(adaptors)):
+		if adaptors[j] - adaptors[i] <= 3:
+			ans += combos(j, counts)
+
+	counts[i] = ans
+	return ans
+
+
+def main() -> None:
+	global adaptors
+	with open("input", "r") as f:
+		adaptors = list(map(int, f.readlines()))
+
+	adaptors.append(0)
+	adaptors.sort()
+	adaptors.append(max(adaptors) + 3)
+
+	print(combos(0))
+
+
+if __name__ == "__main__":
+	main()