2023 day 5.

This commit is contained in:
Mikael CAPELLE 2023-12-05 08:44:44 +01:00
parent b8d8df06d6
commit 8dbf0f101c

View File

@ -1,7 +1,5 @@
import sys
from collections import defaultdict
from dataclasses import dataclass
from typing import Literal, TypeAlias
from typing import Sequence
MAP_ORDER = [
"seed",
@ -16,89 +14,116 @@ MAP_ORDER = [
lines = sys.stdin.read().splitlines()
seeds: list[int] = []
# mappings from one category to another, each list contains
# ranges stored as (source, target, length), ordered by start and
# completed to have no "hole"
maps: dict[tuple[str, str], list[tuple[int, int, int]]] = {}
# parsing
index = 2
while index < len(lines):
l0 = lines[index]
p1, _, p2 = l0.split("-")
p2 = p2.split()[0].strip()
p1, _, p2 = lines[index].split()[0].split("-")
# extract the existing ranges from the file - we store as (source, target, length)
# whereas the file is in order (target, source, length)
index += 1
maps[p1, p2] = []
values: list[tuple[int, int, int]] = []
while index < len(lines) and lines[index]:
n1, n2, n3 = lines[index].split()
maps[p1, p2].append((int(n1), int(n2), int(n3)))
values.append((int(n2), int(n1), int(n3)))
index += 1
# sort by source value
values.sort()
# add a 'fake' interval starting at 0 if missing
if values[0][0] != 0:
values.insert(0, (0, 0, values[0][0]))
# fill gaps between intervals
for i in range(len(values) - 1):
next_start = values[i + 1][0]
end = values[i][0] + values[i][2]
if next_start != end:
values.insert(
i + 1,
(end, end, next_start - end),
)
# add an interval covering values up to at least 2**32 at the end
last_start, _, last_length = values[-1]
values.append((last_start + last_length, last_start + last_length, 2**32))
assert all(v1[0] + v1[2] == v2[0] for v1, v2 in zip(values[:-1], values[1:]))
assert values[0][0] == 0
assert values[-1][0] + values[-1][-1] >= 2**32
maps[p1, p2] = values
index += 1
def find_location(seed: int) -> int:
value = seed
for map1, map2 in zip(MAP_ORDER[:-1], MAP_ORDER[1:]):
for target, start, length in maps[map1, map2]:
if value >= start and value < start + length:
value = target + (value - start)
break
return value
def find_range(
values: tuple[int, int], map: list[tuple[int, int, int]]
) -> list[tuple[int, int]]:
"""
Given an input range, use the given mapping to find the corresponding list of
ranges in the target domain.
"""
r_start, r_length = values
ranges: list[tuple[int, int]] = []
print(r_start, r_length)
for target, start, length in map:
# start is in the range
if start <= r_start and r_start < start + length:
if r_start + r_length < start + length:
ranges.append(
(target + r_start - start, r_length)
)
else:
ranges.append(
(target + r_start - start, length - (r_start - start))
)
elif start < r_start:
if r_start + r_length < start + length:
ranges.append(
(target + r_start - start, target + r_start - start + r_length)
)
elif start >= r_start and r_start >= start
if r_start <= start and start < start + length:
print(start, length, target)
if r_start + r_length < start + length:
ranges.append(
(target + (start - r_start), target + (start - r_start) + length)
)
else:
ranges.append((target + (start - r_start), target + length))
# find index of the first and last intervals in map that overlaps the input
# interval
index_start, index_end = -1, -1
for index_start, (start, _, length) in enumerate(map):
if start <= r_start and start + length > r_start:
break
for index_end, (start, _, length) in enumerate(
map[index_start:], start=index_start
):
if r_start + r_length >= start and r_start + r_length < start + length:
break
assert index_start >= 0 and index_end >= 0
# special case if one interval contains everything
if index_start == index_end:
start, target, length = map[index_start]
ranges.append((target + r_start - start, r_length))
else:
# add the start interval part
start, target, length = map[index_start]
ranges.append((target + r_start - start, start + length - r_start))
# add all intervals between the first and last (excluding both)
index = index_start + 1
while index < index_end:
start, target, length = map[index]
ranges.append((target, length))
index += 1
# add the last interval
start, target, length = map[index_end]
ranges.append((target, r_start + r_length - start))
return ranges
# part 1
seeds = [int(s) for s in lines[0].split(":")[1].strip().split()]
answer_1 = min(find_location(seed) for seed in seeds)
def find_location_ranges(seeds: Sequence[tuple[int, int]]) -> Sequence[tuple[int, int]]:
for map1, map2 in zip(MAP_ORDER[:-1], MAP_ORDER[1:]):
seeds = [s2 for s1 in seeds for s2 in find_range(s1, maps[map1, map2])]
return seeds
# part 1 - use find_range() with range of length 1
seeds_p1 = [(int(s), 1) for s in lines[0].split(":")[1].strip().split()]
answer_1 = min(start for start, _ in find_location_ranges(seeds_p1))
print(f"answer 1 is {answer_1}")
# part 2
# # part 2
parts = lines[0].split(":")[1].strip().split()
seeds_p2 = [(int(s), int(e)) for s, e in zip(parts[::2], parts[1::2])]
for seed in range(seeds_p2[0][0], seeds_p2[0][0] + seeds_p2[0][1]):
print(seed, find_location(seed))
print("---")
seeds_p2 = [seeds_p2[0]]
for map1, map2 in zip(MAP_ORDER[:-1], MAP_ORDER[1:]):
seeds_p2 = [s2 for s1 in seeds_p2 for s2 in find_range(s1, maps[map1, map2])]
print(seeds_p2)
answer_2 = ...
answer_2 = min(start for start, _ in find_location_ranges(seeds_p2))
print(f"answer 2 is {answer_2}")