Advent of Code 2017, Day 10

aoc_2017_day10.py

INPUT = """165,1,255,31,87,52,24,113,0,91,148,254,158,2,73,153"""

import asciitree
from collections import OrderedDict, defaultdict

def _replace(data, position, chunk):
	#print position, chunk
	for idx, v in enumerate(chunk):
		data[position+idx] = v
		
def hash_list(lengths, data, position=0, skip_size=0):
	#print position, skip_size, data
	base_len = len(data)
	for length in lengths:
		#print length
		data = data
		end = position+length
		if end >= base_len:
			data = data + data
		chunk = data[position:end]
		#print position, end, chunk, '->',
		chunk.reverse()
		#print chunk
		if end >= base_len:
			data = data[:base_len]
			before_len = base_len - position
			after_len = length - before_len
			_replace(data, position, chunk[:before_len])
			_replace(data, 0, chunk[before_len:])
		else:
			_replace(data, position, chunk)
		position += (length + skip_size)
		if position >= base_len:
			position = position % base_len
		skip_size += 1
		#print position, skip_size #, data
	return data, position, skip_size
	
def part_one(lengths, base_len):
	data = list(range(base_len))
	position = 0
	skip_size = 0
	data, position, skip_size = hash_list(
		(int(n) for n in lengths.split(",")), 
		data,
		0,
		0,
	)
	return data[0]*data[1]

print part_one("3,4,1,5", 5)
print part_one(INPUT, 256)

def part_two(lengths):
	lengths = [ord(c) for c in lengths] + [17, 31, 73, 47, 23]
	data = list(range(256))
	position = 0
	skip_size = 0
	for __ in range(64):
		data, position, skip_size = hash_list(lengths, data, position, skip_size)
	dense = []
	for offset in range(0, 256, 16):	
		chunk = data[offset:offset+16]
		d = chunk[0]
		for v in chunk[1:]:
			d = d ^ v
		dense.append(d)
		
	return "".join("%02x" % d for d in dense)
	
print part_two(INPUT)