AOC 2017 - day17

Author: Vladimir Makarov

py/advent-of-code-2017/day17.py

@@ -0,0 +1,35 @@
+from typing import List
+
+
+def perform_inserts(steps: int, inserts: int) -> List[int]:
+    circle = [0]
+    pos = 0
+    for i in range(1, inserts + 1):
+        pos = (pos + steps) % len(circle) + 1
+        circle.insert(pos, i)
+    return circle
+
+
+def part1(steps: int) -> int:
+    target = 2017
+    circle = perform_inserts(steps, target)
+    index = circle.index(target) + 1
+    return circle[index % len(circle)]
+
+
+def part2(steps: int) -> int:
+    target = 50000000
+    after_zero = None
+    pos = 0
+    size = 1
+    for i in range(1, target + 1):
+        pos = (pos + steps) % size + 1
+        if pos == 1:
+            after_zero = i
+        size += 1
+    return after_zero
+
+
+steps = 324
+print('Part 1:', part1(steps))
+print('Part 2:', part2(steps))