2022: d20: ex2: add solution

2022/d20/ex2/ex2.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+
+import sys
+from collections import deque
+
+
+def solve(input: list[int]) -> int:
+    def mix(file: list[int], rounds: int) -> list[int]:
+        shuffled = deque(enumerate(file))
+
+        for _ in range(rounds):
+            for i, n in enumerate(file):
+                item = shuffled.index((i, n))
+                shuffled.remove((i, n))
+                # Moving the item to the left means moving the collection to the left
+                shuffled.rotate(-n)
+                shuffled.insert(item, (i, n))
+
+        return [n for _, n in shuffled]
+
+    def coordinates(file: list[int]) -> tuple[int, int, int]:
+        zero_index = file.index(0)
+        indices = map(lambda n: n + zero_index, [1000, 2000, 3000])
+        return tuple(map(lambda n: file[n % len(file)], indices))  # type: ignore
+
+    file = [n * 811589153 for n in input]
+    file = mix(file, 10)
+    return sum(coordinates(file))
+
+
+def main() -> None:
+    input = [int(n) for n in sys.stdin.readlines()]
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()