Anders Englöf Ytterström
d02f63a4ef
Solved by hand by visualizing the filesystem as a grid, and put into a simple formula. In Sweden, this is called a "Femtonspel". https://sv.wikipedia.org/wiki/Femtonspel
58 lines
1.5 KiB
Python
58 lines
1.5 KiB
Python
import re
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from collections import Counter, defaultdict, deque
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from heapq import heappop, heappush
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from itertools import chain, combinations, compress, permutations
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from output import ADJ, DD, D, ints, matrix, mdbg, mhd, vdbg
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def solve(data):
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grid, H, W = matrix(data)
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dests = {
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v: (y, x) for y, r in enumerate(grid) for x, v in enumerate(r) if v.isdigit()
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}
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S0 = dests["0"]
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del dests["0"]
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p1 = travel(dests, grid, H, W, S0)
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p2 = travel(dests, grid, H, W, S0, goback=True)
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return p1, p2
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def travel(dests, grid, H, W, S0, goback=False):
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shortest = float("inf")
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for goals in permutations(dests.items()):
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goals = list(goals)
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if goback:
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goals += [("0", S0)]
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t = 0
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S = S0
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for _, E in goals:
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seen = set()
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q = [(S, 0)]
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while q:
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pos, w = q.pop(0)
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if pos == E:
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t += w
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break
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if pos in seen:
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continue
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seen.add(pos)
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y, x = pos
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for dy, dx in D:
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if not (0 <= dy + y < H and 0 <= dx + x < W):
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continue
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if grid[dy + y][dx + x] != "#":
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q.append(((dy + y, dx + x), w + 1))
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S = E
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shortest = min(shortest, t)
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return shortest
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if __name__ == "__main__":
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with open("./input/24.txt", "r") as f:
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inp = f.read().strip()
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p1, p2 = solve(inp)
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print(p1)
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print(p2)
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