Merge pull request #102 from wimglenn/2023/16

day 16

aoc_wim/aoc2023/q16.py

@@ -0,0 +1,66 @@
+"""
+--- Day 16: The Floor Will Be Lava ---
+https://adventofcode.com/2023/day/16
+"""
+from aocd import data
+from aoc_wim.zgrid import ZGrid
+
+
+def part_a(z0, dz0):
+    paths = []
+    rays = [[(z0, dz0)]]
+    seen = set()
+    while rays:
+        ray = rays[0]
+        if len(ray) > 1 and ray[0] == ray[-1]:
+            paths.append([z for z, dz in ray])
+            del rays[0]
+            continue
+        z, dz = ray[-1]
+        z += dz
+        if (z, dz) in seen:
+            paths.append([z for z, dz in ray])
+            del rays[0]
+            continue
+        seen.add((z, dz))
+        if z not in grid:
+            paths.append([z for z, dz in ray])
+            del rays[0]
+            continue
+        match grid[z], dz.real, dz.imag:
+            case  ".", _, _: ray.append((z, dz))
+            case  "-", _, 0: ray.append((z, dz))
+            case  "|", 0, _: ray.append((z, dz))
+            case  "/", _, 0: ray.append((z, grid.turn_left * dz))
+            case  "/", 0, _: ray.append((z, grid.turn_right * dz))
+            case "\\", _, 0: ray.append((z, grid.turn_right * dz))
+            case "\\", 0, _: ray.append((z, grid.turn_left * dz))
+            case "|", _, 0:
+                paths.append([z for z, dz in ray])
+                del rays[0]
+                if z + grid.up in grid:
+                    rays.append([(z, grid.up)])
+                if z + grid.down in grid:
+                    rays.append([(z, grid.down)])
+            case "-", 0, _:
+                paths.append([z for z, dz in ray])
+                del rays[0]
+                if z + grid.left in grid:
+                    rays.append([(z, grid.left)])
+                if z + grid.right in grid:
+                    rays.append([(z, grid.right)])
+    return len({z for z, dz in seen if z in grid})
+
+
+grid = ZGrid(data)
+print("answer_a:", part_a(z0=-1, dz0=1))
+
+w, h = grid.width, grid.height
+bs = []
+for col in range(w):
+    bs.append(part_a(z0=complex(col, -1j), dz0=grid.down))
+    bs.append(part_a(z0=complex(col, h), dz0=grid.up))
+for row in range(h):
+    bs.append(part_a(z0=complex(-1, row), dz0=grid.right))
+    bs.append(part_a(z0=complex(w, row), dz0=grid.left))
+print("answer_b:", max(bs))

tests/2023/15/0.txt

@@ -1,3 +1,3 @@
 rn=1,cm-,qp=3,cm=2,qp-,pc=4,ot=9,ab=5,pc-,pc=6,ot=7
 1320
--
+145

tests/2023/16/0.txt

@@ -0,0 +1,12 @@
+.|...\....
+|.-.\.....
+.....|-...
+........|.
+..........
+.........\
+..../.\\..
+.-.-/..|..
+.|....-|.\
+..//.|....
+46
+51