From 08fd489704409e1d7414ff51bdac5d789cabb668 Mon Sep 17 00:00:00 2001
From: Nat Lasseter <user@4574.co.uk>
Date: Thu, 6 Dec 2018 12:07:00 +0000
Subject: [day06] Done

---
 day06/part2 | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100755 day06/part2

(limited to 'day06/part2')

diff --git a/day06/part2 b/day06/part2
new file mode 100755
index 0000000..dc74890
--- /dev/null
+++ b/day06/part2
@@ -0,0 +1,30 @@
+#!/usr/bin/env ruby
+
+def manhattan_distance(x, y, p)
+  return (x - p.first).abs + (y - p.last).abs
+end
+
+input = $stdin.readlines.map(&:chomp).map{|i|i.split(", ").map(&:to_i)}
+MAX_DISTANCE = 10000
+
+xoff = input.map(&:first).min - 1
+yoff = input.map(&:last).min - 1
+
+input.each do |p|
+  p[0] -= xoff
+  p[1] -= yoff
+end
+
+wid = input.map(&:first).max + 1
+hei = input.map(&:last).max + 1
+
+grid = Array.new(wid) { Array.new(hei, false) }
+
+(0...wid).each do |x|
+  (0...hei).each do |y|
+    dist_sum = input.map{|p|manhattan_distance(x, y, p)}.sum
+    grid[x][y] = true if dist_sum < MAX_DISTANCE
+  end
+end
+
+puts grid.flatten.count(true)
-- 
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