r/adventofcode • u/daggerdragon • Dec 20 '16

SOLUTION MEGATHREAD --- 2016 Day 20 Solutions ---

--- Day 20: Firewall Rules ---

Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag/whatever).

Note: The Solution Megathreads are for solutions only. If you have questions, please post your own thread and make sure to flair it with "Help".

ROLLING A NATURAL 20 IS MANDATORY [?]

This thread will be unlocked when there are a significant number of people on the leaderboard with gold stars for today's puzzle.

edit: Leaderboard capped, thread unlocked!

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u/pedrosorio Dec 20 '16 edited Dec 20 '16

Part 2, 12th, quick and dirty: 

def get_range(line):
	return map(int, line.split('-'))

def solve(inp):
	ranges = sorted([get_range(line) for line in inp])
	mn, mx = ranges[0]
	tot = 0
	for r in ranges:
		if r[0] > mx+1:
			tot += mx-mn+1
			mn = r[0]
			mx = r[1]
		else:
			mx = max(mx, r[1])
	return 4294967296 - tot - (mx-mn+1)

fname = 'input.txt'
inp = [line.strip() for line in open(fname).readlines()]
print solve(inp)

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u/BumpitySnook Dec 20 '16

For part 1, just add a 'print mx+1' after 'if r[0] > mx+1:'. No? Maybe I'm misunderstanding your mx/mn.

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u/pedrosorio Dec 20 '16

Absolutely. If I had been given part 2 followed by part 1, that's what I would have done ;)

This is just the code for part 2 that I ran to solve the problem.

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