81 lines
1.9 KiB
Python
81 lines
1.9 KiB
Python
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up = lambda v: (v[0], v[1] + 1)
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down = lambda v: (v[0], v[1] - 1)
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left = lambda v: (v[0] - 1, v[1])
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right = lambda v: (v[0] + 1, v[1])
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moves = {'U' : up,
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'D' : down,
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'L' : left,
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'R' : right
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}
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def memoize(f):
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cache = dict()
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def memf(path):
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if path not in cache:
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cache[path] = f(path)
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return cache[path]
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return memf
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def iterate(f, x, N):
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for i in range(N):
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yield x
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x = f(x)
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@memoize
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def lines(path):
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pos = (0, 0)
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r = []
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for move in path.split(','):
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dir, steps = move[0], int(move[1:])
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line = list(iterate(moves[dir], pos, steps+1))
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r.append(line)
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pos = line[-1]
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return r
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def coordinates(path, corners=True):
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return sum((line[1:len(line) - 1 + corners]
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for line in lines(path)), [])
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def crossings(*paths):
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return set.intersection(*(set(coordinates(path, corners=False))
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for path in paths))
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def min_crossing(path1, path2, f):
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return min(f(v) for v in crossings(path1, path2))
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def preproc(puzzle_input):
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return puzzle_input.split()
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def partI(paths):
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key = lambda v: abs(v[0]) + abs(v[1])
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path1, path2 = paths
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return min_crossing(path1, path2, key)
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def partII(paths):
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path1, path2 = paths
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def key(c1, c2):
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r = lambda v: c1.index(v) + c2.index(v) + 2
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return r
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def min_steps(p1, p2):
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c1, c2 = coordinates(p1), coordinates(p2)
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return min_crossing(p1, p2, key(c1, c2))
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return min_steps(path1, path2)
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import solver
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tests = solver.Tests()
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tests.add("R75,D30,R83,U83,L12,D49,R71,U7,L72\n" +
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"U62,R66,U55,R34,D71,R55,D58,R83",
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partI=159,
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partII=610)
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tests.add("R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51\n" +
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"U98,R91,D20,R16,D67,R40,U7,R15,U6,R7",
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partI=135,
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partII=410)
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