--- Day 21: Monkey Math ---
The monkeys are back! You're worried they're going to try to steal your stuff again, but it seems like they're just holding their ground and making various monkey noises at you.
Eventually, one of the elephants realizes you don't speak monkey and comes over to interpret. As it turns out, they overheard you talking about trying to find the grove; they can show you a shortcut if you answer their riddle.
Each monkey is given a job: either to yell a specific number or to yell the result of a math operation. All of the number-yelling monkeys know their number from the start; however, the math operation monkeys need to wait for two other monkeys to yell a number, and those two other monkeys might also be waiting on other monkeys.
Your job is to work out the number the monkey named
root will yell before the monkeys figure it out themselves.
root: pppw + sjmn dbpl: 5 cczh: sllz + lgvd zczc: 2 ptdq: humn - dvpt dvpt: 3 lfqf: 4 humn: 5 ljgn: 2 sjmn: drzm * dbpl sllz: 4 pppw: cczh / lfqf lgvd: ljgn * ptdq drzm: hmdt - zczc hmdt: 32
Each line contains the name of a monkey, a colon, and then the job of that monkey:
- A lone number means the monkey's job is simply to yell that number.
- A job like
aaaa + bbbbmeans the monkey waits for monkeys
bbbbto yell each of their numbers; the monkey then yells the sum of those two numbers.
aaaa - bbbbmeans the monkey yells
aaaa's number minus
aaaa * bbbbwill yell
aaaa's number multiplied by
aaaa / bbbbwill yell
aaaa's number divided by
So, in the above example, monkey
drzm has to wait for monkeys
zczc to yell their numbers. Fortunately, both
zczc have jobs that involve simply yelling a single number, so they do this immediately:
drzm can then yell its number by finding
sjmn has one of its numbers (
30, from monkey
drzm), and already has its other number,
dbpl. This allows it to yell its own number by finding
30 multiplied by
This process continues until
root yells a number:
However, your actual situation involves considerably more monkeys. What number will the monkey named