https://adventofcode.com/2022/day/11

This solution relies on the fact that there are no interactions between items, so each item can be simulated separately. When a monkey throws an item to a monkey with a larger ID that monkey will get to throw the item in the same round, but when it throws it to an earlier monkey, that item will not be thrown until the next round. Using this we can keep track of when an item would stop moving.

>>> :{
:main +
  "Monkey 0:\n\
  \  Starting items: 79, 98\n\
  \  Operation: new = old * 19\n\
  \  Test: divisible by 23\n\
  \    If true: throw to monkey 2\n\
  \    If false: throw to monkey 3\n\
  \\n\
  \Monkey 1:\n\
  \  Starting items: 54, 65, 75, 74\n\
  \  Operation: new = old + 6\n\
  \  Test: divisible by 19\n\
  \    If true: throw to monkey 2\n\
  \    If false: throw to monkey 0\n\
  \\n\
  \Monkey 2:\n\
  \  Starting items: 79, 60, 97\n\
  \  Operation: new = old * old\n\
  \  Test: divisible by 13\n\
  \    If true: throw to monkey 1\n\
  \    If false: throw to monkey 3\n\
  \\n\
  \Monkey 3:\n\
  \  Starting items: 74\n\
  \  Operation: new = old + 3\n\
  \  Test: divisible by 17\n\
  \    If true: throw to monkey 0\n\
  \    If false: throw to monkey 1\n"
:}
10605
2713310158