Why on earch

aoc2020/day03/solution.py

@@ -1,3 +1,4 @@
+import functools
 import sys
 import typing
 
@@ -11,21 +12,39 @@ def main() -> int:
     forest_frame = [list(line.strip()) for line in sys.stdin.readlines()]
     frame_width = len(forest_frame[0])
     frame_height = len(forest_frame)
-    loc = Loc(x=0, y=0)
 
-    trees_encountered = 0
-
-    while loc.y <= (frame_height - 1):
-        at_loc = forest_frame[loc.y][loc.x]
-        if at_loc == "#":
-            trees_encountered += 1
-
-        next_x = (loc.x + 3) % frame_width
-        next_y = loc.y + 1
-        next_loc = Loc(x=next_x, y=next_y)
-        loc = next_loc
-
-    print(f"trees encountered: {trees_encountered}")
+    all_trees_encountered = []
+
+    for slope in [
+        Loc(x=1, y=1),
+        Loc(x=3, y=1),
+        Loc(x=5, y=1),
+        Loc(x=7, y=1),
+        Loc(x=1, y=2),
+    ]:
+        loc = Loc(x=0, y=0)
+
+        trees_encountered = 0
+
+        while loc.y <= (frame_height - 1):
+            at_loc = forest_frame[loc.y][loc.x]
+            if at_loc == "#":
+                trees_encountered += 1
+
+            next_x = (loc.x + slope.x) % frame_width
+            next_y = loc.y + slope.y
+            next_loc = Loc(x=next_x, y=next_y)
+            loc = next_loc
+
+        print(
+            f"(slope right={slope.x} down={slope.y}) trees encountered: {trees_encountered}"
+        )
+        all_trees_encountered.append(trees_encountered)
+
+    trees_encountered_product = functools.reduce(
+        lambda x, y: x * y, all_trees_encountered
+    )
+    print(f"trees encountered product: {trees_encountered_product}")
     return 0