mirror of
https://github.com/Threnklyn/advent-of-code-go.git
synced 2026-06-03 18:58:27 +02:00
alexchao26
122 lines
3.2 KiB
Python
122 lines
3.2 KiB
Python
from dataclasses import dataclass
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# index by index brute force with a sliding window optimization to make it linear...
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def part1(input: str) -> int:
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total_disk_space: int = 0
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for x in list(input):
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total_disk_space += int(x)
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file_system: list[int] = [-1] * total_disk_space
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is_file: bool = True
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index: int = 0
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file_number: int = 0
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for x in list(input):
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if not is_file:
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index += int(x)
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is_file = not is_file
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else:
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for _ in range(int(x)):
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if is_file:
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file_system[index] = file_number
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index += 1
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file_number += 1
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is_file = not is_file
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# rearrange file to left via sliding window
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left: int = 0
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right: int = len(file_system) - 1
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while left < right:
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if file_system[right] == -1:
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right -= 1
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elif file_system[left] != -1:
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left += 1
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elif file_system[left] == -1:
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file_system[left], file_system[right] = (
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file_system[right],
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file_system[left],
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)
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left += 1
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# checksum is index in string * number value (file number)
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checksum: int = 0
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for i in range(len(file_system)):
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if file_system[i] == -1:
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break
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checksum += i * file_system[i]
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return checksum
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@dataclass
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class FileSystemSpace:
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start: int
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size: int
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file_number: int
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def part2(input: str) -> int:
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files: list[FileSystemSpace] = []
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empty_spaces: list[FileSystemSpace] = []
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is_file: bool = True
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index: int = 0
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for size in [int(x) for x in list(input)]:
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file_or_empty = FileSystemSpace(index, size, len(files))
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index += size
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if is_file:
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files.append(file_or_empty)
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else:
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empty_spaces.append(file_or_empty)
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is_file = not is_file
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# brute force finding a space to move each file into
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for file in reversed(files):
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for empty_space in empty_spaces:
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# prevent moving files to higher spots in the file system...
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if empty_space.start > file.start:
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break
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# large enough empty space found
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if empty_space.size >= file.size:
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file.start = empty_space.start
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empty_space.start += file.size
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empty_space.size -= file.size
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break
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# print_util(files)
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checksum: int = 0
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for file in files:
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for x in range(file.size):
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checksum += (file.start + x) * file.file_number
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return checksum
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def print_util(all_files: list[FileSystemSpace]):
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last_index: int = 0
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for file in all_files:
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last_index = max(last_index, file.start + file.size)
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fs: list[str] = ["."] * (last_index + 1)
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for file in all_files:
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for i in range(file.start, file.start + file.size):
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fs[i] = str(file.file_number)
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print("".join(fs))
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example = """2333133121414131402"""
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input = open("input.txt").read().strip()
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print(f"part1 example: {part1(example)} want 1928")
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print(f"part1: {part1(input)} want 6200294120911")
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print(f"part2 example: {part2(example)} want 2858")
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print(f"part2: {part2(input)} want 6227018762750")
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