Fractal Art — Python — #adventofcode Day 21
Series
This post is part of the series Advent of Code 2017
- Reflections on #aoc2017
- The Halting Problem — Python — #adventofcode Day 25
- Electromagnetic Moat — Rust — #adventofcode Day 24
- Coprocessor Conflagration — Haskell — #adventofcode Day 23
- Sporifica Virus — Rust — #adventofcode Day 22
- > Fractal Art — Python — #adventofcode Day 21 <
- Particle Swarm — Python — #adventofcode Day 20
- A Series of Tubes — Rust — #adventofcode Day 19
- Duet — Haskell — #adventofcode Day 18
- Spinlock — Rust/Python — #adventofcode Day 17
- Permutation Promenade — Julia — #adventofcode Day 16
- Dueling Generators — Rust — #adventofcode Day 15
- Disk Defragmentation — Haskell — #adventofcode Day 14
- Packet Scanners — Haskell — #adventofcode Day 13
- Digital Plumber — Python — #adventofcode Day 12
- Hex Ed — Python — #adventofcode Day 11
- Knot Hash — Haskell — #adventofcode Day 10
- Stream Processing — Haskell — #adventofcode Day 9
- I Heard You Like Registers — Python — #adventofcode Day 8
- Recursive Circus — Ruby — #adventofcode Day 7
- Memory Reallocation — Python — #adventofcode Day 6
- A Maze of Twisty Trampolines — C++ — #adventofcode Day 5
- High Entropy Passphrases — Python — #adventofcode Day 4
- Spiral Memory — Go — #adventofcode Day 3
- Corruption Checksum — Python — #adventofcode Day 2
- Inverse Captcha — Coconut — #adventofcode Day 1
- Advent of Code 2017: introduction
Series:
Advent of Code 2017
Today’s challenge asks us to assist an artist building fractal patterns from a rulebook.
!!! commentary Another fairly straightforward algorithm: the really tricky part was breaking the pattern up into chunks and rejoining it again. I could probably have done that more efficiently, and would have needed to if I had to go for a few more iterations and the grid grows with every iteration and gets big fast.
Still behind on the blog posts…
import fileinput as fi
from math import sqrt
from functools import reduce, partial
import operator
INITIAL_PATTERN = ((0, 1, 0), (0, 0, 1), (1, 1, 1))
DECODE = ['.', '#']
ENCODE = {'.': 0, '#': 1}
concat = partial(reduce, operator.concat)
def rotate(p):
size = len(p)
return tuple(tuple(p[i][j] for i in range(size))
for j in range(size - 1, -1, -1))
def flip(p):
return tuple(p[i] for i in range(len(p) - 1, -1, -1))
def permutations(p):
yield p
yield flip(p)
for _ in range(3):
p = rotate(p)
yield p
yield flip(p)
def print_pattern(p):
print('-' * len(p))
for row in p:
print(' '.join(DECODE[x] for x in row))
print('-' * len(p))
def build_pattern(s):
return tuple(tuple(ENCODE[c] for c in row)
for row in s.split('/'))
def build_pattern_book(lines):
book = {}
for line in lines:
source, target = line.strip().split(' => ')
for rotation in permutations(build_pattern(source)):
book[rotation] = build_pattern(target)
return book
def subdivide(pattern):
size = 2 if len(pattern) % 2 == 0 else 3
n = len(pattern) // size
return (tuple(tuple(pattern[i][j] for j in range(y * size, (y + 1) * size))
for i in range(x * size, (x + 1) * size))
for x in range(n)
for y in range(n))
def rejoin(parts):
n = int(sqrt(len(parts)))
size = len(parts[0])
return tuple(concat(parts[i + k][j] for i in range(n))
for k in range(0, len(parts), n)
for j in range(size))
def enhance_once(p, book):
return rejoin(tuple(book[part] for part in subdivide(p)))
def enhance(p, book, n, progress=None):
for _ in range(n):
p = enhance_once(p, book)
return p
book = build_pattern_book(fi.input())
intermediate_pattern = enhance(INITIAL_PATTERN, book, 5)
print("After 5 iterations:", sum(sum(row) for row in intermediate_pattern))
final_pattern = enhance(intermediate_pattern, book, 13)
print("After 18 iterations:", sum(sum(row) for row in final_pattern))
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