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advent-of-code-2k23/day5/day5.py
2023-12-05 17:55:40 +01:00

65 lines
1.9 KiB
Python

from itertools import zip_longest
def grouper(n, iterable, fillvalue=None):
"grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx"
args = [iter(iterable)] * n
return zip_longest(fillvalue=fillvalue, *args)
def part1(sections):
# consume seed section
_, seeds = next(sections)
seeds = [int(s) for s in seeds]
print(seeds)
for name, numbers in sections:
# item: range_start, len, offset
#mapping = []
#for dst, src, length in grouper(3, numbers):
#mapping.append((src, lenght, dst))
#src = range(int(src), int(src) + int(length))
#dst = range(int(dst), int(dst) + int(length))
#for k, v in zip(src, dst):
# mapping[k] = v
# apply current mapping on input (using linear search)
new_seeds = []
for seed in seeds:
for dst, src, length in grouper(3, numbers):
src, length, dst = int(src), int(length), int(dst)
end = dst + (length - 1)
if src <= seed < end:
new_seed = seed + (dst-src)
new_seeds.append(new_seed)
break
else:
new_seeds.append(seed)
seeds = new_seeds
print(seeds)
#seeds = [mapping.get(s, None) or s for s in seeds]
print(f"Part 1, lowest location number = {min(seeds)}")
def parse_input(infile):
with open(infile) as f:
sections = f.read().split("\n\n")
sections = ((title, numbers) for title, numbers in (s.split(":") for s in sections))
sections = ((title, numbers.split()) for title, numbers in sections)
return sections
if __name__ == "__main__":
import sys
import os
SCRIPTPATH = os.path.dirname(os.path.realpath(__file__))
infile = next(iter(sys.argv[1:]), None)
sections = parse_input(infile or os.path.join(SCRIPTPATH, "example.txt"))
part1(sections)