Solution to Day 14: Disk Defragmentation

advent_of_code_d14.py

#aoc_d14.py


def knot_hash(inputstr):
	skip_size = 0
	inp = range(0,256)
	ind = 0
	for i in range(0,64):
		lengths = [ord(c) for c in inputstr]
		add = [17, 31, 73, 47, 23]
		lengths = lengths + add
		#print lengths
		for l in lengths:
			w = []
			for i in range(ind,ind+l):
				w.append(inp[i%len(inp)])
			rev = w[::-1]
			o = {}
			for i in range(ind,ind+l):
				o[i%len(inp)] = rev[i-ind]
			n = [None]*len(inp)
			for i in range(0,len(inp)):
				if i in o:
					n[i]= o[i]
				else:
					n[i] = inp[i]
			inp = n
			ind = (ind + (l + skip_size)) % len(inp)
			skip_size += 1

	res = ''
	for i in range(0,16):
		w = inp[i*16:(i+1)*16]
		z = w[0]
		for r in range(1,len(w)):
			z = z ^ w[r]
		res += '{:02x}'.format(z)
	return res

sum_bits = 0
for i in range(128):
	r = knot_hash("stpzcrnm-"+str(i))
	sum_bits += bin(int(r,16)).count("1")
	print i,r, sum_bits