From 8ed0896adb5e72949b3067a5e0d208b8e496ac80 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Tue, 15 Dec 2020 22:05:25 -0800
Subject: [PATCH] Add unclean day16 solution.

---
 day16.cr | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 day16.cr

diff --git a/day16.cr b/day16.cr
new file mode 100644
index 0000000..f9aa8b9
--- /dev/null
+++ b/day16.cr
@@ -0,0 +1,65 @@
+require "advent"
+
+def parse_range(str)
+  data = str.match(/([a-z ]+): (\d+)-(\d+) or (\d+)-(\d+)/).not_nil!
+  return {data[1], (data[2].to_i32..data[3].to_i32), (data[4].to_i32.. data[5].to_i32)}
+end
+
+fields, your, nearby = input(2020, 16).split("\n\n")
+fields = fields.lines.map { |l| parse_range(l) }
+your = your.lines[1].split(",").map(&.to_i32)
+nearby = nearby.lines[1..].map(&.split(",").map(&.to_i32))
+
+def part1(input)
+  fields, your, nearby = input
+  all_ranges = [] of Range(Int32, Int32)
+  fields.each do |a|
+    all_ranges << a[1] << a[2]
+  end
+  nearby.select! do |nb|
+    nb.all? do |n|
+      all_ranges.any? &.includes?(n)
+    end
+  end
+  nearby << your
+  field_map = {} of String => Set(Int32)
+  fields.each do |f|
+    field_map[f[0]] = Set(Int32).new
+    nearby[0].size.times do |i|
+      next if field_map.values.includes? i
+      all_match = nearby.all? do |nb|
+        f[1].includes?(nb[i]) || f[2].includes?(nb[i])
+      end
+      if all_match
+        field_map[f[0]] << i
+      end
+    end
+  end
+  sum = 1_u64
+  numbers = (0...nearby[0].size).to_a
+  solved = {} of String => Int32
+  while solved.size != fields.size
+    cleared = [] of {String, Int32}
+    field_map.each do |k, v|
+      next unless v.size == 1
+      cleared << {k, v.to_a[0]}
+    end
+    cleared.each do |f,n|
+      solved[f] = n
+      field_map.each do |k, v|
+        v.delete n
+      end
+    end
+  end
+  fields.each do |f|
+    next unless f[0].starts_with? "departure"
+    sum *= your[solved[f[0]]]
+  end
+  sum
+end
+
+def part2(input)
+end
+
+puts part1({fields, your, nearby})
+puts part2({fields, your, nearby})