import 2020 aoc

2020/day10/day10.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+from collections import Counter
+
+
+def part1(adapters):
+    counts = Counter()
+    # 1 for the socket, of 3 for the device
+    for current, next in zip([0] + adapters, adapters + [3]):
+        counts[next - current] += 1
+    return counts[1] * counts[3]
+
+
+def part2(adapters):
+    counts = Counter({0: 1})
+    for jolt in adapters:
+        s = counts[jolt - 1] + counts[jolt - 2] + counts[jolt - 3]
+        counts[jolt] = s
+    return max(counts.values())
+
+
+if __name__ == "__main__":
+    adapters = sorted(int(l.rstrip()) for l in open("input.txt"))
+    print(part1(adapters))
+    print(part2(adapters))