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# Day 11: Monkey in the Middle
import std/[os, strutils, sequtils, sugar, algorithm]
import npeg # https://github.com/zevv/npeg
let input = paramStr(1).readFile().strip().split("\n\n")
type Monkey = object
stuff: seq[int]
inspect: (int) -> int
throw: (int) -> int
count: int
var monkey: Monkey
var monkees: seq[Monkey]
let parser = peg(input):
input <- +(group * "\n\n")
group <- monkey * "\n" * starting * "\n" * operation * "\n" * test :
monkees.add(monkey)
monkey <- "Monkey " * >Digit * ":":
monkey = Monkey()
starting <- " Starting items: " * >+Digit * *(", " * >+Digit):
monkey.stuff = capture[1 ..< capture.len].mapIt(parseInt(it.s))
operation <- " Operation: new = old " * >("+" | "*") * " " * >("old" | +Digit):
let op =
if $1 == "+":
(x, y: int) => x + y
else:
(x, y: int) => x * y
if $2 == "old":
monkey.inspect = (x: int) => x.op(x)
else:
monkey.inspect = (x: int) => x.op(parseInt($2))
test <- " Test: divisible by " * >+Digit * "\n" * success * "\n" * failure:
monkey.throw = (x: int) => (if x mod parseInt($1) == 0: parseInt($2) else: parseInt($3))
success <- " If true: throw to monkey " * >Digit
failure <- " If false: throw to monkey " * >Digit
assert parser.match(paramStr(1).readFile().strip()).ok == true
let lcm = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29][0 ..< monkees.len].foldl(a*b, 1)
var monkeys = monkees
for _ in 0 ..< 20:
for i, monkey in monkeys:
while monkeys[i].stuff.len > 0:
var worry = monkeys[i].stuff.pop()
monkeys[i].count += 1
worry = monkeys[i].inspect(worry)
worry = worry div 3
monkeys[monkeys[i].throw(worry)].stuff.add(worry)
echo monkeys.mapIt(it.count).sorted(Descending)[0..1].foldl(a*b, 1)
monkeys = monkees
for _ in 0 ..< 10000:
for i in 0 ..< monkeys.len:
while monkeys[i].stuff.len > 0:
var worry = monkeys[i].stuff.pop()
monkeys[i].count += 1
worry = monkeys[i].inspect(worry)
worry = worry mod lcm
monkeys[monkeys[i].throw(worry)].stuff.add(worry)
echo monkeys.mapIt(it.count).sorted(Descending)[0..1].foldl(a*b, 1)
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