98 lines
2.7 KiB
Python
98 lines
2.7 KiB
Python
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from collections import defaultdict
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from itertools import combinations, permutations
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with open("input19.txt") as f:
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lines = [line.rstrip() for line in f]
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scanners = []
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for line in lines:
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if line.startswith("--"):
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scanner_id = int(line.split()[2])
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positions = []
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elif line:
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positions.append(tuple(map(int, line.split(","))))
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else:
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scanners.append((scanner_id, positions))
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scanners.append((scanner_id, positions))
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def N(x, y, z): return x, y, z
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def X(x, y, z): return x, -z, y
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def Y(x, y, z): return -z, y, x
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def add(v1, v2): return v1[0] + v2[0], v1[1] + v2[1], v1[2] + v2[2]
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def sub(v1, v2): return v1[0] - v2[0], v1[1] - v2[1], v1[2] - v2[2]
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orientations = [
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"N", "X", "Y", "XX", "XY", "YX", "YY", "XXX", "XXY", "XYX", "XYY", "YXX",
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"YYX", "YYY", "XXXY", "XXYX", "XXYY", "XYXX", "XYYY", "YXXX", "YYYX",
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"XXXYX", "XYXXX", "XYYYX"
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]
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rotations = {k: globals()[k] for k in "NXY"}
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def orient(x, y, z, orientation):
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for axis in orientation:
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x, y, z = rotations[axis[::-1]](x, y, z)
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return x, y, z
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overlaps = {}
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oriented = {
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sb_id: [(o, [orient(*pos, o) for pos in sb]) for o in orientations]
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for sb_id, sb in scanners
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}
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# Using permutations is slower than combinations but it's simpler to find the
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# transform path after.
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for (sa_id, sa), (sb_id, _) in permutations(scanners, 2):
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for orientation, osb in oriented[sb_id]:
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diffs = defaultdict(int)
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for ax, ay, az in sa:
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for bx, by, bz in osb:
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diff = (ax - bx, ay - by, az - bz)
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diffs[diff] += 1
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if diffs[diff] >= 12:
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overlaps[(sa_id, sb_id)] = (orientation, diff)
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break
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else:
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continue
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break
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else:
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continue
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break
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def find_transform_to_0(from_s):
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chains = [[p] for p in overlaps if p[0] == from_s]
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seen = set()
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while chains:
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chain = chains.pop(0)
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if chain[-1][1] == 0:
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return chain
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for p in overlaps:
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if p[0] == chain[-1][1] and p not in seen:
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seen.add(p)
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chains.append(chain + [p])
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def see_as_0(x, y, z, sid):
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for t in find_transform_to_0(sid):
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ori, move = overlaps[t[::-1]]
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x, y, z = add(orient(x, y, z, ori), move)
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return x, y, z
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def see_scanner_as_0(sid, sdata):
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for x, y, z in sdata:
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yield see_as_0(x, y, z, sid)
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beacons = set()
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for scanner_id in range(len(scanners)):
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beacons |= set(list(see_scanner_as_0(*scanners[scanner_id])))
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print(len(beacons))
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scanner_positions = [see_as_0(0, 0, 0, sid) for sid in range(len(scanners))]
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print(max(
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sum(map(abs, sub(spb, spa)))
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for spa, spb in combinations(scanner_positions, 2)
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))
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