You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
100 lines
2.6 KiB
100 lines
2.6 KiB
#!/usr/bin/env julia
|
|
|
|
using Test
|
|
|
|
mutable struct Monkey
|
|
index :: UInt
|
|
items :: Vector{Int}
|
|
op :: Function
|
|
op_value :: Int
|
|
test_divisor :: Int
|
|
test_result :: NTuple{2, UInt}
|
|
inspected :: Int
|
|
end
|
|
|
|
function parse_monkey(text)
|
|
lines = split(text, '\n')
|
|
# Monkey 0:
|
|
match_index = match(r"Monkey (\d+):", lines[1])
|
|
index = parse(UInt, match_index.captures[1])
|
|
# Starting items: 79, 98
|
|
match_items = match(r" *Starting items: (.*)", lines[2])
|
|
items_list = split(match_items.captures[1], ", ")
|
|
items = parse.(Int, items_list)
|
|
# Operation: new = old * 19
|
|
match_op = match(r" *Operation: new = old (.) (old|\d+)", lines[3])
|
|
if match_op.captures[1] == "+"
|
|
op = +
|
|
elseif match_op.captures[1] == "*"
|
|
op = *
|
|
else
|
|
throw(DomainError("Unknown op: " * match_op.captures[1]))
|
|
end
|
|
if match_op.captures[2] == "old"
|
|
op = ^
|
|
op_value = 2
|
|
else
|
|
op_value = parse(Int, match_op.captures[2])
|
|
end
|
|
# Test: divisible by 13
|
|
match_test = match(r" *Test: divisible by (\d+)", lines[4])
|
|
test_divisor = parse(Int, match_test.captures[1])
|
|
# If true: throw to monkey 1
|
|
# If false: throw to monkey 3
|
|
match_true = match(r" *If true: throw to monkey (\d+)", lines[5])
|
|
match_false = match(r" *If false: throw to monkey (\d+)", lines[6])
|
|
test_result = (parse(UInt, match_true.captures[1]) + 1,
|
|
parse(UInt, match_false.captures[1]) + 1)
|
|
return Monkey(index, items, op, op_value, test_divisor, test_result, 0)
|
|
end
|
|
|
|
function read_monkeys(infile)
|
|
open(infile) do io
|
|
monkey_strings = split(read(io, String), "\n\n")
|
|
return parse_monkey.(monkey_strings)
|
|
end
|
|
end
|
|
|
|
function simian_shenanigans(monkeys :: Vector{Monkey})
|
|
for m in monkeys
|
|
for item in m.items
|
|
new_value = m.op(item, m.op_value)
|
|
new_value = Int(floor(new_value / 3))
|
|
new_monkey = (mod(new_value, m.test_divisor) == 0
|
|
? m.test_result[1] : m.test_result[2])
|
|
push!(monkeys[new_monkey].items, new_value)
|
|
m.inspected += 1
|
|
end
|
|
empty!(m.items)
|
|
end
|
|
end
|
|
|
|
function monkey_business(monkeys; rounds=20)
|
|
for _ in 1:rounds
|
|
simian_shenanigans(monkeys)
|
|
end
|
|
return prod(sort([m.inspected for m in monkeys])[end-1:end])
|
|
end
|
|
|
|
function test()
|
|
@testset "monkey business" verbose=true begin
|
|
@test monkey_business(read_monkeys("example.txt")) == 10605
|
|
@test monkey_business(read_monkeys("input.txt")) == 64032
|
|
end
|
|
end
|
|
|
|
function main()
|
|
if size(ARGS, 1) == 0
|
|
test()
|
|
else
|
|
infile = ARGS[1]
|
|
println("infile = ", infile)
|
|
monkeys = read_monkeys(infile)
|
|
display(monkeys)
|
|
println()
|
|
println("monkey business ", monkey_business(monkeys))
|
|
end
|
|
end
|
|
|
|
main()
|