Add day 11 code

day11.cr

@@ -0,0 +1,58 @@
+require "advent"
+require "big"
+
+class Monkey
+  property items : Array(Int64)
+  property op : String
+  property divBy : Int64
+  property ifTrue : Int64
+  property ifFalse : Int64
+
+  def initialize(@items, @op, @divBy, @ifTrue, @ifFalse)
+  end
+end
+
+INSTS = {
+  "*" => ->(x: Int64, y: Int64) { x * y },
+  "+" => ->(x: Int64, y: Int64) { x + y }
+}
+
+def execute(inst, old, mod)
+  inst = inst.gsub("old", old.to_s);
+  l, op, r = inst.split(" ")
+  l = l.to_i64 % mod
+  r = r.to_i64 % mod
+  INSTS[op].call(l,r)
+end
+
+monkeys = [] of Monkey
+input(2022, 11).split("\n\n").each do |it|
+  it = it.lines
+  items = it[1].split(": ")[1].split(", ").map(&.to_i64).reverse
+  op = it[2].split("Operation: new = ")[1]
+  divBy = it[3].split("Test: divisible by ")[1].to_i64
+  ifTrue = it[4].split("  If true: throw to monkey ")[1].to_i64
+  ifFalse = it[5].split("  If false: throw to monkey ")[1].to_i64
+  monkeys << Monkey.new(items, op, divBy, ifTrue, ifFalse)
+end
+
+counts = [0] * monkeys.size
+modulus = monkeys.map(&.divBy).product
+10000.times do
+  monkeys.each_with_index do |m, i|
+    while !m.items.empty?
+      counts[i] += 1
+      item = m.items.pop
+      item = execute(m.op, item, modulus)
+      item = item % modulus
+      if item % m.divBy == 0
+        monkeys[m.ifTrue].items.insert(0, item)
+      else
+        monkeys[m.ifFalse].items.insert(0, item)
+      end
+    end
+  end
+end
+
+counts.sort!
+puts counts[-1].to_big_i * counts[-2].to_big_i