From 8a7eab81e0afeef3de4f133970860a880b089d1f Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Mon, 7 Dec 2020 02:36:36 -0800
Subject: [PATCH] Solve a few more puzzles.

---
 day10.cr          | 72 +++++++++++++++++++++++++++++++++++++++++++++++
 day11.cr          | 42 +++++++++++++++++++++++++++
 day7.cr           |  6 ++--
 day8.cr           | 19 +++++++++++++
 day9.cr           |  7 +++++
 intcode_fibers.cr | 47 ++++++++++++++++++++++---------
 6 files changed, 176 insertions(+), 17 deletions(-)
 create mode 100644 day10.cr
 create mode 100644 day11.cr
 create mode 100644 day8.cr
 create mode 100644 day9.cr

diff --git a/day10.cr b/day10.cr
new file mode 100644
index 0000000..13641f2
--- /dev/null
+++ b/day10.cr
@@ -0,0 +1,72 @@
+require "advent"
+
+struct Tuple(*T)
+  def reduce_fraction
+    gcd = (self[0].gcd self[1]).abs
+    return self if gcd == 0
+    {self[0] // gcd, self[1]//gcd}
+  end
+end
+
+struct Tuple(*T)
+  def -(other)
+    {self[0]-other[0], self[1] - other[1]}
+  end
+
+  def dist
+    self[0] + self[1]
+  end
+end
+
+input = input(2019, 10)
+asteroids = Set({Int32, Int32}).new
+input.lines.each_with_index do |l, y|
+  l.chars.each_with_index do |c, x|
+    next unless c == '#'
+    asteroids << {x, y}
+  end
+end
+
+p1 = asteroids.max_of do |a|
+  angles = Set({Int32, Int32}).new
+  asteroids.each do |b|
+    next if a == b
+    angles << (b-a).reduce_fraction
+  end
+  angles.size
+end
+
+puts p1
+
+p2s = asteroids.max_by do |a|
+  angles = Set({Int32, Int32}).new
+  asteroids.each do |b|
+    next if a == b
+    angles << (b-a).reduce_fraction
+  end
+  angles.size
+end
+
+angle_groups = asteroids.group_by do |a|
+  (a - p2s).reduce_fraction
+end
+angle_groups.delete({0,0})
+angle_groups.each do |k, v|
+  v.sort! do |a|
+    (a - p2s).dist
+  end
+end
+
+angles = angle_groups.keys.sort_by do |k|
+  -Math.atan2(k[0].to_f32, k[1].to_f32)
+end
+i = 1
+angles.cycle do |angle|
+  next if angle_groups[angle].empty?
+  asteroid = angle_groups[angle].delete_at(0)
+  if i == 200
+    puts asteroid[0] * 100 + asteroid[1]
+    break
+  end
+  i += 1
+end
diff --git a/day11.cr b/day11.cr
new file mode 100644
index 0000000..2ab3f31
--- /dev/null
+++ b/day11.cr
@@ -0,0 +1,42 @@
+require "advent"
+require "./intcode_fibers.cr"
+
+painted_white = Set({Int64, Int64}).new
+color = {} of {Int64,Int64} => Int64
+color[{0_i64, 0_i64}] = 1_i64
+input, output = new_interpreter("", input(2019, 11).split(",").map &.to_i64)
+pos = {0_i64, 0_i64}
+facing = {0_i64, 1_i64}
+
+struct Tuple(*T)
+  def turn_left
+    {-self[1], self[0]}
+  end
+
+  def turn_right
+    turn_left.turn_left.turn_left
+  end
+
+  def add(other)
+    {self[0] + other[0], self[1] + other[1]}
+  end
+end
+
+loop do
+  c = color[pos]? || 0_i64
+  input.send c
+  break unless nc = output.receive
+  break unless turn = output.receive
+  color[pos] = nc
+  painted_white << pos if nc == 1
+  facing = (turn == 0 ? facing.turn_left : facing.turn_right)
+  pos = pos.add facing
+end
+
+6.times do |y|
+  y = - y
+  45.times do |x|
+    print (color[{x.to_i64, y.to_i64}]? == 1 ? '#' : ' ')
+  end
+  puts
+end
diff --git a/day7.cr b/day7.cr
index e8ed3b4..e8fc144 100644
--- a/day7.cr
+++ b/day7.cr
@@ -1,18 +1,18 @@
 require "./intcode.cr"
 require "./intcode_fibers.cr"
 
-prog = File.read("day7.txt").chomp.split(",").map(&.to_i32)
+prog = File.read("day7.txt").chomp.split(",").map(&.to_i64)
 
 def chain_amplifiers(prog, perm, loop = false)
   chans = perm.map { |f| new_interpreter(f, prog) }
   chans.zip perm do |amp, freq|
-    amp[0].send freq
+    amp[0].send freq.to_i64
   end
 
   chans[0][0].send 0
 
   i = 0
-  history = Array(Int32).new(chans.size, 0)
+  history = Array(Int64).new(chans.size, 0)
   loop do
     j = (i+1) % chans.size
     break unless received = chans[i][1].receive
diff --git a/day8.cr b/day8.cr
new file mode 100644
index 0000000..aefc8de
--- /dev/null
+++ b/day8.cr
@@ -0,0 +1,19 @@
+require "advent"
+
+input = input(2019, 8).chomp
+layers = input.chars.each_slice(25*6).to_a
+layer = layers.min_by(&.count('0'))
+puts(layer.count('2') * layer.count('1'))
+
+message = layers.reduce do |l1, l2|
+  l1.zip_with(l2) do |a1, a2|
+    next (a1 == '2') ? a2 : a1
+  end
+end
+
+6.times do |i|
+  25.times do |j|
+    print(message[25*i+j] == '1' ? '#' : ' ')
+  end
+  puts
+end
diff --git a/day9.cr b/day9.cr
new file mode 100644
index 0000000..9fa6387
--- /dev/null
+++ b/day9.cr
@@ -0,0 +1,7 @@
+require "advent"
+require "./intcode_fibers.cr"
+
+input = input(2019, 9).split(",").map &.to_i64
+input, output = new_interpreter("", input)
+input.send 2_i64
+puts output.receive
diff --git a/intcode_fibers.cr b/intcode_fibers.cr
index 18ee2e1..6604ab1 100644
--- a/intcode_fibers.cr
+++ b/intcode_fibers.cr
@@ -1,40 +1,59 @@
-def new_interpreter(f, prog)
-  prog = prog.clone
-  input = Channel(Int32).new
-  output = Channel(Int32?).new
+def new_interpreter(f, p)
+  prog = {} of Int64 => Int64
+  p.each_with_index do |v, i|
+    prog[i.to_i64] = v.to_i64
+  end
+
+  input = Channel(Int64).new
+  output = Channel(Int64?).new
   spawn do
     op = ""
-    pc = 0
-    arg = ->(i : Int32) { op[-(3+i)] == '0' ? prog[prog[pc+1+i]] : prog[pc+1+i] }
+    pc = 0_i64
+    base = 0_i64
+    index = ->(i : Int32) {
+      case op[-(3+i)]
+      when '0'
+        prog[pc+1+i]
+      when '1'
+        pc+1+i
+      else
+        prog[pc+1+i] + base
+      end
+    }
+    get = ->(i : Int32) { prog[index.call(i)]? || 0_i64 }
+    set = ->(i : Int32, v : Int64) { prog[index.call(i)] = v }
     loop do
       op = "0000" + prog[pc].to_s
       case op
       when .ends_with? "1"
-        prog[prog[pc+3]] = arg.call(0) + arg.call(1)
+        set.call(2, get.call(0) + get.call(1))
         pc += 4
       when .ends_with? "2"
-        prog[prog[pc+3]] = arg.call(0) * arg.call(1)
+        set.call(2, get.call(0) * get.call(1))
         pc += 4
       when .ends_with? "3"
-        prog[prog[pc+1]] = input.receive
+        set.call(0, input.receive)
         pc += 2
       when .ends_with? "4"
-        output.send(arg.call(0))
+        output.send(get.call(0))
         pc += 2
       when .ends_with? "5"
-        pc = arg.call(0) != 0 ? arg.call(1) : pc + 3
+        pc = get.call(0) != 0 ? get.call(1) : pc + 3
       when .ends_with? "6"
-        pc = arg.call(0) == 0 ? arg.call(1) : pc + 3
+        pc = get.call(0) == 0 ? get.call(1) : pc + 3
       when .ends_with? "7"
-        prog[prog[pc+3]] = arg.call(0) < arg.call(1) ? 1 : 0
+        set.call(2, get.call(0) < get.call(1) ? 1_i64 : 0_i64)
         pc += 4
       when .ends_with? "8"
-        prog[prog[pc+3]] = arg.call(0) ==  arg.call(1) ? 1 : 0
+        set.call(2, get.call(0) == get.call(1) ? 1_i64 : 0_i64)
         pc += 4
       when .ends_with? "99"
         input.receive
         output.send(nil)
         break
+      when .ends_with? "9"
+        base += get.call(0)
+        pc += 2
       end
     end
   end