Solution Day 25: The Halting Problem

advent_of_code_d25.py

#aoc_d25.py

tape = {}
state = 'A'
pos = 0

for i in range(12794428): #12794428
	if pos not in tape:
		tape[pos] = 0
	if state == 'A':
		if tape[pos] == 0:
			tape[pos] = 1
			pos+=1
			state = 'B'
		elif tape[pos] == 1:
			tape[pos] = 0
			pos-=1
			state = 'F'
	elif state == 'B':
		if tape[pos] == 0:
			tape[pos] = 0
			pos+=1
			state = 'C'
		elif tape[pos] == 1:
			tape[pos] = 0
			pos+=1
			state = 'D'
	elif state == 'C':
		if tape[pos] == 0:
			tape[pos] = 1
			pos-=1
			state = 'D'
		elif tape[pos] == 1:
			tape[pos] = 1
			pos+=1
			state = 'E'
	elif state == 'D':
		if tape[pos] == 0:
			tape[pos] = 0
			pos-=1
			state = 'E'
		elif tape[pos] == 1:
			tape[pos] = 0
			pos-=1
			state = 'D'
	elif state == 'E':
		if tape[pos] == 0:
			tape[pos] = 0
			pos+=1
			state = 'A'
		elif tape[pos] == 1:
			tape[pos] = 1
			pos+=1
			state = 'C'
	elif state == 'F':
		if tape[pos] == 0:
			tape[pos] = 1
			pos-=1
			state = 'A'
		elif tape[pos] == 1:
			tape[pos] = 1
			pos+=1
			state = 'A'

print tape
print sum(tape[x] == 1 for x in tape)