day11 p2

day11/day11.jl

@@ -55,11 +55,16 @@ function read_monkeys(infile)
   end
 end
 
-function simian_shenanigans(monkeys :: Vector{Monkey})
+function simian_shenanigans(monkeys :: Vector{Monkey}; part=1)
+  modulus = prod(m.test_divisor for m in monkeys)
   for m in monkeys
     for item in m.items
       new_value = m.op(item, m.op_value)
+      if part == 1
         new_value = Int(floor(new_value / 3))
+      else
+        new_value = mod(new_value, modulus)
+      end
       new_monkey = (mod(new_value, m.test_divisor) == 0
                     ? m.test_result[1] : m.test_result[2])
       push!(monkeys[new_monkey].items, new_value)
@@ -69,18 +74,24 @@ function simian_shenanigans(monkeys :: Vector{Monkey})
   end
 end
 
-function monkey_business(monkeys; rounds=20)
+function monkey_business(monkeys; rounds=20, part=1)
   for _ in 1:rounds
-    simian_shenanigans(monkeys)
+    simian_shenanigans(monkeys, part=part)
   end
   return prod(sort([m.inspected for m in monkeys])[end-1:end])
 end
 
 function test()
-  @testset "monkey business" verbose=true begin
+  @testset "monkey business 1" verbose=true begin
     @test monkey_business(read_monkeys("example.txt")) == 10605
     @test monkey_business(read_monkeys("input.txt")) == 64032
   end
+  @testset "monkey business 2" verbose=true begin
+    @test monkey_business(
+            read_monkeys("example.txt"), rounds=10000, part=2) == 2713310158
+    @test monkey_business(
+            read_monkeys("input.txt"), rounds=10000, part=2) == 12729522272
+  end
 end
 
 function main()
@@ -92,7 +103,12 @@ function main()
     monkeys = read_monkeys(infile)
     display(monkeys)
     println()
-    println("monkey business ", monkey_business(monkeys))
+    println("monkey business 1 ",
+            monkey_business(monkeys, rounds=20, part=1))
+
+    monkeys = read_monkeys(infile)
+    println("monkey business 2 ",
+            monkey_business(monkeys, rounds=10000, part=2))
   end
 end