aoc2017-day13

import sys

import re

def selfprint(x):

print(x)

return x

def one_by_one(inputf):

return ([int(__)

for __ in _.split()]

for _ in

(re.sub("[:]", " ", _)

for _ in

(_.strip()

for _ in iter(inputf))

if _))

def scanner_pos(tick, depth):

x = depth - 1

p = x - abs(x - tick % (2*x))

return p

def positions(tick, firewalls):

return ((_, scanner_pos(tick + _[0], _[1])) for _ in firewalls)

def collisions(tick, firewalls, pos):

return ((f, p == pos) for f, p in positions(tick, firewalls) if p == pos)

def has_next(seq):

return next((True for _ in seq), False)

def compute_weight(seq):

return sum((f[0] * f[1] for f,_ in seq))

with sys.stdin as f:

firewalls = list(one_by_one(f))

print(compute_weight(collisions(0, firewalls, 0)))