Advent of Code 2017, Day 13

aoc_2017_day13.py

INPUT = """0: 3
1: 2
2: 4
4: 6
6: 5
8: 8
10: 6
12: 4
14: 8
16: 6
18: 8
20: 8
22: 6
24: 8
26: 9
28: 12
30: 8
32: 14
34: 10
36: 12
38: 12
40: 10
42: 12
44: 12
46: 12
48: 12
50: 14
52: 12
54: 14
56: 12
60: 14
62: 12
64: 14
66: 14
68: 14
70: 14
72: 14
74: 14
78: 26
80: 18
82: 17
86: 18
88: 14
96: 18"""

TEST = """0: 3
1: 2
4: 4
6: 4"""

from collections import defaultdict
from functools import partial

def read_input(input):
	ports = {}
	for line in input.splitlines():
		idx, depth = map(int, line.split(": "))
		ports[idx] = depth
	#print ports
	num_ports = max(ports.keys())
	return [ports.get(idx, 1) for idx in range(num_ports+1)]

def _is_scanning(depth, picosecond):
	if depth == 1:
		return False
	else:
		return (picosecond % ((depth-1) * 2)) == 0
		
def once_through(ports, picosecond=0, stop_if_caught=False):
	tot_severity = 0
	times_caught = 0
	start_picosecond = picosecond
	for idx, depth in enumerate(ports):
		if 0:
			print idx, start_picosecond, picosecond
			print "   ", " ".join("%5s" % d for d in ports)
			print "   ", " ".join("%5s" % _is_scanning(d, picosecond) for d in ports)
			print
		if _is_scanning(depth, picosecond):
			if stop_if_caught:
				if 0:
					print idx, start_picosecond, picosecond, "CAUGHT"
					print "   ", " ".join("%5s" % d for d in ports)
					print "   ", " ".join("%5s" % _is_scanning(d, picosecond) for d in ports)
					print
				return 1, 0
			else:
				tot_severity += depth * idx
				times_caught += 1
		picosecond += 1
		
	return times_caught, tot_severity
	
def part_one(input):
	ports = read_input(input)
	times_caught, tot_severity = once_through(ports, picosecond=0, stop_if_caught=False)
	return tot_severity
		
print part_one(TEST)
print part_one(INPUT)


def part_two(input):
	ports = read_input(input)
	start_picosecond = 0
	while True:
		if not start_picosecond % 10000:
			print start_picosecond
		times_caught, tot_severity = once_through(ports, picosecond=start_picosecond, stop_if_caught=True)
		if times_caught == 0:
			return start_picosecond
		start_picosecond += 1

	return start_picosecond
	
print part_two(TEST)
print part_two(INPUT)