My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add solution for 2023/05
It's not fast... but it's a solution.
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2023/day05.py
+59
2023/day05.py
···
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import fileinput
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import itertools
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def seed_to_location(mappings, seed):
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curr = seed
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for mapping in mappings:
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for dest, src, rng in mapping:
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if src <= curr <= src + rng:
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curr += (dest - src)
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break
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return curr
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def location_to_seed(mappings, location):
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curr = location
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for mapping in reversed(mappings):
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for dest, src, rng in mapping:
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if dest <= curr < dest + rng:
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curr -= (dest - src)
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break
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return curr
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def seed_in_start_range(cand, seed_starts, seed_ranges):
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for start, rng in zip(seed_starts, seed_ranges):
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if start <= cand < start + rng:
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return True
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return False
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# Parse problem input.
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file = ''.join(fileinput.input())[:-1]
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seeds, *raw_mappings = file.split('\n\n')
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seeds = [int(x) for x in seeds.split()[1:]]
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mappings = []
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for m in raw_mappings:
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nums = m.split('\n')[1:]
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mapping = [[int(x) for x in line.split()] for line in nums]
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mappings.append(mapping)
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# Solve Part 1.
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print("Part 1:", min(seed_to_location(mappings, seed) for seed in seeds))
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# Solve Part 2.
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seed_starts = seeds[::2]
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seed_ranges = seeds[1::2]
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for location in itertools.count(start=1):
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seed = location_to_seed(mappings, location)
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if seed_in_start_range(seed, seed_starts, seed_ranges):
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break
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print("Part 2:", location)
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