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- #!/usr/bin/python3
-
- import math
- import operator
-
-
- def steps(start, delta, count):
- sign = int(math.copysign(1, delta))
- return [start] * count if delta == 0 else range(start + sign, start + delta + sign, sign)
-
- with open('data/01.txt', 'r') as file:
- input = file.read()
-
- movement_lookup = {'L': -1, 'R': +1}
- direction_lookup = {0: (0, -1), 1: (1, 0), 2: (0, 1), 3: (-1, 0)}
-
- moves = [(movement_lookup[move[0]], int(move[1:])) for move in input.split(', ')]
-
- heading = 0
- history = [(0, 0)]
- for move in moves:
- heading = (heading + move[0]) % 4
- delta = list(map(operator.mul, direction_lookup[heading], (move[1], move[1])))
- delta_mag = max(abs(delta[0]), abs(delta[1]))
- history += zip(steps(history[-1][0], delta[0], delta_mag),
- steps(history[-1][1], delta[1], delta_mag))
-
- duplicates = (x for n, x in enumerate(history) if history[:n].count(x) > 0)
- overlap = next(duplicates)
-
- print("Part 1: %s ==> %s" % (history[-1], abs(history[-1][0]) + abs(history[-1][1])))
- print("Part 2: %s ==> %s" % (overlap, abs(overlap[0]) + abs(overlap[1])))
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