My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add 2022/22
+160
+160
2022/day22.py
+160
2022/day22.py
···
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import re, fileinput
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from utils import min_max_xy
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from utils import firsts, lasts
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from utils import Point, DIRS
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# Read problem input.
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graph = {}
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in_maze = True
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start = None
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for y, line in enumerate(fileinput.input()):
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if not line.strip():
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in_maze = False
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if in_maze:
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for x, c in enumerate(line.strip("\n")):
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if c != ' ':
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if start is None and c == '.':
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start = Point(x, -y)
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graph[Point(x, -y)] = c
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else:
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instructions = re.findall(r'(\d+|[LR])', line)
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def wrapped_links(graph):
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"""Compute link dictionary for part 1."""
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links = {}
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min_x, max_x, min_y, max_y = min_max_xy(list(graph.keys()))
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# Construct the left-to-right wrap-around links.
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for y in range(min_y, max_y + 1):
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first = None
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for x in range(min_x, max_x + 1):
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p = Point(x, y)
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if first is None and p in graph:
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first = p
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elif p in graph:
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last = p
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links[last, 1] = (first, 1)
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links[first, 3] = (last, 3)
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# Construct the top-to-bottom wrap-around links.
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for x in range(min_x, max_x + 1):
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first = None
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for y in range(min_y, max_y + 1):
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p = Point(x, y)
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if first is None and p in graph:
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first = p
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elif p in graph:
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last = p
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links[last, 0] = (first, 0)
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links[first, 2] = (last, 2)
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return links
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def cube_links():
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"""
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This works specifically for my cube, which is shaped as follows:
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1122
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1122
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4455
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4455
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"""
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links = {}
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# Define 2D arrays representing the 6 different faces of the cube, as numbered
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# above, in the orientation given by the problem input.
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FS = 50
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f1 = [[Point(x, -y) for x in range(FS*1, FS*2)] for y in range(FS*0, FS*1)]
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f2 = [[Point(x, -y) for x in range(FS*2, FS*3)] for y in range(FS*0, FS*1)]
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f3 = [[Point(x, -y) for x in range(FS*1, FS*2)] for y in range(FS*1, FS*2)]
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f4 = [[Point(x, -y) for x in range(FS*0, FS*1)] for y in range(FS*2, FS*3)]
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f5 = [[Point(x, -y) for x in range(FS*1, FS*2)] for y in range(FS*2, FS*3)]
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f6 = [[Point(x, -y) for x in range(FS*0, FS*1)] for y in range(FS*3, FS*4)]
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# "Glue together" the appropriate edges of each of the face pairs that will
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# be touching when the cube is formed. The "facing" direction changes depending
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# on which direction you're coming into the point from.
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for p, np in zip(f1[0], reversed(firsts(f6))):
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links[(p, 0)] = (np, 1)
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links[(np, 3)] = (p, 2)
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for p, np in zip(firsts(f1), reversed(firsts(f4))):
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links[(p, 3)] = (np, 1)
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links[(np, 3)] = (p, 1)
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for p, np in zip(f2[0], f6[-1]):
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links[(p, 0)] = (np, 0)
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links[(np, 2)] = (p, 2)
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for p, np in zip(reversed(lasts(f2)), lasts(f5)):
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links[(p, 1)] = (np, 3)
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links[(np, 1)] = (p, 3)
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for p, np in zip(f2[-1], reversed(lasts(f3))):
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links[(p, 2)] = (np, 3)
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links[(np, 1)] = (p, 0)
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for p, np in zip(firsts(f3), reversed(f4[0])):
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links[(p, 3)] = (np, 2)
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links[(np, 0)] = (p, 1)
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for p, np in zip(f5[-1], reversed(lasts(f6))):
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links[(p, 2)] = (np, 3)
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links[(np, 1)] = (p, 0)
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return links
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def simulate(graph, start, instructions, links):
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pos = start
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dir = 1
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for ins in instructions:
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# Turn clockwise or counterclockwise.
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if not ins.isnumeric():
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if ins == 'L':
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dir = (dir - 1) % 4
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else:
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dir = (dir + 1) % 4
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continue
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# Move some number of steps (or stop at a wall).
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for _ in range(int(ins)):
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np = pos + DIRS[dir]
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# Bump into a wall, stop going forward.
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if graph.get(np) == '#':
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break
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elif graph.get(np) == '.':
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pos = np
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continue
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else:
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# We need to wrap around to another spot. The link mapping
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# tells us what the new position is, and what our new facing is.
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np, nf = links[pos, dir]
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if graph.get(np) == '#':
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break
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elif graph.get(np) == '.':
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pos = np
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dir = nf
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continue
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row = -pos.y + 1
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col = pos.x + 1
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facing = (dir - 1) % 4
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return (1000 * row) + (4 * col) + facing
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print("Part 1:", simulate(graph, start, instructions, wrapped_links(graph)))
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print("Part 2:", simulate(graph, start, instructions, cube_links()))