eh bored again

2018/01/01.exs

@@ -1,12 +1,13 @@
 list = File.read!("input.txt")
-|> String.split("\n")
+|> String.split(~r/\R/)
 |> Enum.map(&String.to_integer/1)
 
 ans1 = list
 |> Enum.sum()
 IO.puts(ans1)
 
-reducer = fn i, {current, seen} -> frequency = current + i
+reducer = fn i, {current, seen} ->
+	frequency = current + i
 	if MapSet.member?(seen, frequency) do
 		{:halt, frequency}
 	else

2018/01/01.py

@@ -0,0 +1,45 @@
+with open("input.txt") as f:
+	lines = f.read().splitlines()
+
+freqs = [int(line) for line in lines]
+print("Part 1:", sum(freqs))
+
+## what follows is a O(n log n) solution using modulos to avoid cycling manually.
+## personally i just did it in elixir with Stream.cycle()...
+
+from itertools import accumulate
+sums = [0] + list(accumulate(freqs))
+seen = set()
+
+# check first cycle
+for s in sums:
+	if s in seen:
+		ans2 = s
+	seen.add(s)
+
+# check if last element is 0 (can't do mod 0)
+tail = sums[-1]
+if tail == 0:
+	ans2 = 0
+
+# calculate mapping of all mods and indexes
+sums = sums[:-1] # the last sum is part of the next iteration -- we start at 0
+from collections import defaultdict
+mods = defaultdict(list)
+for i, s in enumerate(sums):
+	mods[s % tail].append((i,s))
+
+mini, mind, minf = None, None, None
+for m in mods.values():
+	ss = list(sorted(m, key = lambda t: t[1])) # sort by second element of tuple
+	for i in range(1,len(ss)):
+		diff = ss[i][1] - ss[i-1][1]
+		index = ss[i-1][0] if tail > 0 else ss[i][0]
+		freq = ss[i][1] if tail > 0 else ss[i-1][1]
+		if mind is None or diff < mind or (diff == mind and index < mini):
+			mini = index
+			mind = diff
+			minf = freq
+
+ans2 = minf
+print("Part 2:", ans2)

2018/03/03.py

@@ -0,0 +1,26 @@
+with open("input.txt") as f:
+	lines = f.read().splitlines()
+
+import re
+claims = [[*map(int, re.findall(r'\d+', line))] for line in lines]
+
+from collections import Counter
+fabric = Counter(
+	(i,j)
+	for id, x, y, width, height in claims
+	for i in range(x,x+width)
+	for j in range(y,y+height)
+	)
+
+ans1 = sum(1 for c in fabric.values() if c > 1) # more than 1 claim
+print("Part 1:",ans1)
+
+ans2 = next(
+	id
+	for id, x, y, width, height in claims
+	if all(fabric[(i,j)] == 1
+		for i in range(x,x+width)
+		for j in range(y,y+height)
+		)
+	)
+print("Part 2:",ans2)