2016: d02: ex2: add solution

2016/d02/ex2/ex2.py

@@ -0,0 +1,73 @@
+#!/usr/bin/env python
+
+import enum
+import sys
+from typing import NamedTuple
+
+
+class Point(NamedTuple):
+    x: int
+    y: int
+
+
+class Direction(enum.StrEnum):
+    UP = "U"
+    DOWN = "D"
+    LEFT = "L"
+    RIGHT = "R"
+
+    def apply(self, p: Point) -> Point:
+        match self:
+            case Direction.UP:
+                dx, dy = -1, 0
+            case Direction.DOWN:
+                dx, dy = 1, 0
+            case Direction.LEFT:
+                dx, dy = 0, -1
+            case Direction.RIGHT:
+                dx, dy = 0, 1
+        return Point(p.x + dx, p.y + dy)
+
+
+def solve(input: str) -> str:
+    def parse(input: str) -> list[list[Direction]]:
+        return [[Direction(c) for c in line] for line in input.splitlines()]
+
+    def enter_code(directions: list[list[Direction]]) -> str:
+        KEYPAD = {
+            Point(-2, 2): "1",
+            Point(-1, 1): "2",
+            Point(-1, 2): "3",
+            Point(-1, 3): "4",
+            Point(0, 0): "5",
+            Point(0, 1): "6",
+            Point(0, 2): "7",
+            Point(0, 3): "8",
+            Point(0, 4): "9",
+            Point(1, 1): "A",
+            Point(1, 2): "B",
+            Point(1, 3): "C",
+            Point(2, 2): "D",
+        }
+        letters = []
+        pos = Point(0, 0)
+        for line in directions:
+            for d in line:
+                new_pos = d.apply(pos)
+                if new_pos not in KEYPAD:
+                    continue
+                pos = new_pos
+            letters.append(KEYPAD[pos])
+        return "".join(letters)
+
+    directions = parse(input)
+    return enter_code(directions)
+
+
+def main() -> None:
+    input = sys.stdin.read()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()