2022 day 11: Bash parts 1 & 2, before cleaning

2022/day11/README.org

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+** --- Day 11: Monkey in the Middle ---
+As you finally start making your way upriver, you realize your pack is
+much lighter than you remember. Just then, one of the items from your
+pack goes flying overhead. Monkeys are playing
+[[https://en.wikipedia.org/wiki/Keep_away][Keep Away]] with your missing
+things!
+
+To get your stuff back, you need to be able to predict where the monkeys
+will throw your items. After some careful observation, you realize the
+monkeys operate based on /how worried you are about each item/.
+
+You take some notes (your puzzle input) on the items each monkey
+currently has, how worried you are about those items, and how the monkey
+makes decisions based on your worry level. For example:
+
+#+begin_example
+Monkey 0:
+  Starting items: 79, 98
+  Operation: new = old * 19
+  Test: divisible by 23
+    If true: throw to monkey 2
+    If false: throw to monkey 3
+
+Monkey 1:
+  Starting items: 54, 65, 75, 74
+  Operation: new = old + 6
+  Test: divisible by 19
+    If true: throw to monkey 2
+    If false: throw to monkey 0
+
+Monkey 2:
+  Starting items: 79, 60, 97
+  Operation: new = old * old
+  Test: divisible by 13
+    If true: throw to monkey 1
+    If false: throw to monkey 3
+
+Monkey 3:
+  Starting items: 74
+  Operation: new = old + 3
+  Test: divisible by 17
+    If true: throw to monkey 0
+    If false: throw to monkey 1
+#+end_example
+
+Each monkey has several attributes:
+
+- =Starting items= lists your /worry level/ for each item the monkey is
+  currently holding in the order they will be inspected.
+- =Operation= shows how your worry level changes as that monkey inspects
+  an item. (An operation like =new = old * 5= means that your worry
+  level after the monkey inspected the item is five times whatever your
+  worry level was before inspection.)
+- =Test= shows how the monkey uses your worry level to decide where to
+  throw an item next.
+  - =If true= shows what happens with an item if the =Test= was true.
+  - =If false= shows what happens with an item if the =Test= was false.
+
+After each monkey inspects an item but before it tests your worry level,
+your relief that the monkey's inspection didn't damage the item causes
+your worry level to be /divided by three/ and rounded down to the
+nearest integer.
+
+The monkeys take turns inspecting and throwing items. On a single
+monkey's /turn/, it inspects and throws all of the items it is holding
+one at a time and in the order listed. Monkey =0= goes first, then
+monkey =1=, and so on until each monkey has had one turn. The process of
+each monkey taking a single turn is called a /round/.
+
+When a monkey throws an item to another monkey, the item goes on the
+/end/ of the recipient monkey's list. A monkey that starts a round with
+no items could end up inspecting and throwing many items by the time its
+turn comes around. If a monkey is holding no items at the start of its
+turn, its turn ends.
+
+In the above example, the first round proceeds as follows:
+
+#+begin_example
+Monkey 0:
+  Monkey inspects an item with a worry level of 79.
+    Worry level is multiplied by 19 to 1501.
+    Monkey gets bored with item. Worry level is divided by 3 to 500.
+    Current worry level is not divisible by 23.
+    Item with worry level 500 is thrown to monkey 3.
+  Monkey inspects an item with a worry level of 98.
+    Worry level is multiplied by 19 to 1862.
+    Monkey gets bored with item. Worry level is divided by 3 to 620.
+    Current worry level is not divisible by 23.
+    Item with worry level 620 is thrown to monkey 3.
+Monkey 1:
+  Monkey inspects an item with a worry level of 54.
+    Worry level increases by 6 to 60.
+    Monkey gets bored with item. Worry level is divided by 3 to 20.
+    Current worry level is not divisible by 19.
+    Item with worry level 20 is thrown to monkey 0.
+  Monkey inspects an item with a worry level of 65.
+    Worry level increases by 6 to 71.
+    Monkey gets bored with item. Worry level is divided by 3 to 23.
+    Current worry level is not divisible by 19.
+    Item with worry level 23 is thrown to monkey 0.
+  Monkey inspects an item with a worry level of 75.
+    Worry level increases by 6 to 81.
+    Monkey gets bored with item. Worry level is divided by 3 to 27.
+    Current worry level is not divisible by 19.
+    Item with worry level 27 is thrown to monkey 0.
+  Monkey inspects an item with a worry level of 74.
+    Worry level increases by 6 to 80.
+    Monkey gets bored with item. Worry level is divided by 3 to 26.
+    Current worry level is not divisible by 19.
+    Item with worry level 26 is thrown to monkey 0.
+Monkey 2:
+  Monkey inspects an item with a worry level of 79.
+    Worry level is multiplied by itself to 6241.
+    Monkey gets bored with item. Worry level is divided by 3 to 2080.
+    Current worry level is divisible by 13.
+    Item with worry level 2080 is thrown to monkey 1.
+  Monkey inspects an item with a worry level of 60.
+    Worry level is multiplied by itself to 3600.
+    Monkey gets bored with item. Worry level is divided by 3 to 1200.
+    Current worry level is not divisible by 13.
+    Item with worry level 1200 is thrown to monkey 3.
+  Monkey inspects an item with a worry level of 97.
+    Worry level is multiplied by itself to 9409.
+    Monkey gets bored with item. Worry level is divided by 3 to 3136.
+    Current worry level is not divisible by 13.
+    Item with worry level 3136 is thrown to monkey 3.
+Monkey 3:
+  Monkey inspects an item with a worry level of 74.
+    Worry level increases by 3 to 77.
+    Monkey gets bored with item. Worry level is divided by 3 to 25.
+    Current worry level is not divisible by 17.
+    Item with worry level 25 is thrown to monkey 1.
+  Monkey inspects an item with a worry level of 500.
+    Worry level increases by 3 to 503.
+    Monkey gets bored with item. Worry level is divided by 3 to 167.
+    Current worry level is not divisible by 17.
+    Item with worry level 167 is thrown to monkey 1.
+  Monkey inspects an item with a worry level of 620.
+    Worry level increases by 3 to 623.
+    Monkey gets bored with item. Worry level is divided by 3 to 207.
+    Current worry level is not divisible by 17.
+    Item with worry level 207 is thrown to monkey 1.
+  Monkey inspects an item with a worry level of 1200.
+    Worry level increases by 3 to 1203.
+    Monkey gets bored with item. Worry level is divided by 3 to 401.
+    Current worry level is not divisible by 17.
+    Item with worry level 401 is thrown to monkey 1.
+  Monkey inspects an item with a worry level of 3136.
+    Worry level increases by 3 to 3139.
+    Monkey gets bored with item. Worry level is divided by 3 to 1046.
+    Current worry level is not divisible by 17.
+    Item with worry level 1046 is thrown to monkey 1.
+#+end_example
+
+After round 1, the monkeys are holding items with these worry levels:
+
+#+begin_example
+Monkey 0: 20, 23, 27, 26
+Monkey 1: 2080, 25, 167, 207, 401, 1046
+Monkey 2:
+Monkey 3:
+#+end_example
+
+Monkeys 2 and 3 aren't holding any items at the end of the round; they
+both inspected items during the round and threw them all before the
+round ended.
+
+This process continues for a few more rounds:
+
+#+begin_example
+After round 2, the monkeys are holding items with these worry levels:
+Monkey 0: 695, 10, 71, 135, 350
+Monkey 1: 43, 49, 58, 55, 362
+Monkey 2:
+Monkey 3:
+
+After round 3, the monkeys are holding items with these worry levels:
+Monkey 0: 16, 18, 21, 20, 122
+Monkey 1: 1468, 22, 150, 286, 739
+Monkey 2:
+Monkey 3:
+
+After round 4, the monkeys are holding items with these worry levels:
+Monkey 0: 491, 9, 52, 97, 248, 34
+Monkey 1: 39, 45, 43, 258
+Monkey 2:
+Monkey 3:
+
+After round 5, the monkeys are holding items with these worry levels:
+Monkey 0: 15, 17, 16, 88, 1037
+Monkey 1: 20, 110, 205, 524, 72
+Monkey 2:
+Monkey 3:
+
+After round 6, the monkeys are holding items with these worry levels:
+Monkey 0: 8, 70, 176, 26, 34
+Monkey 1: 481, 32, 36, 186, 2190
+Monkey 2:
+Monkey 3:
+
+After round 7, the monkeys are holding items with these worry levels:
+Monkey 0: 162, 12, 14, 64, 732, 17
+Monkey 1: 148, 372, 55, 72
+Monkey 2:
+Monkey 3:
+
+After round 8, the monkeys are holding items with these worry levels:
+Monkey 0: 51, 126, 20, 26, 136
+Monkey 1: 343, 26, 30, 1546, 36
+Monkey 2:
+Monkey 3:
+
+After round 9, the monkeys are holding items with these worry levels:
+Monkey 0: 116, 10, 12, 517, 14
+Monkey 1: 108, 267, 43, 55, 288
+Monkey 2:
+Monkey 3:
+
+After round 10, the monkeys are holding items with these worry levels:
+Monkey 0: 91, 16, 20, 98
+Monkey 1: 481, 245, 22, 26, 1092, 30
+Monkey 2:
+Monkey 3:
+
+...
+
+After round 15, the monkeys are holding items with these worry levels:
+Monkey 0: 83, 44, 8, 184, 9, 20, 26, 102
+Monkey 1: 110, 36
+Monkey 2:
+Monkey 3:
+
+...
+
+After round 20, the monkeys are holding items with these worry levels:
+Monkey 0: 10, 12, 14, 26, 34
+Monkey 1: 245, 93, 53, 199, 115
+Monkey 2:
+Monkey 3:
+#+end_example
+
+Chasing all of the monkeys at once is impossible; you're going to have
+to focus on the /two most active/ monkeys if you want any hope of
+getting your stuff back. Count the /total number of times each monkey
+inspects items/ over 20 rounds:
+
+#+begin_example
+Monkey 0 inspected items 101 times.
+Monkey 1 inspected items 95 times.
+Monkey 2 inspected items 7 times.
+Monkey 3 inspected items 105 times.
+#+end_example
+
+In this example, the two most active monkeys inspected items 101 and 105
+times. The level of /monkey business/ in this situation can be found by
+multiplying these together: =10605=.
+
+Figure out which monkeys to chase by counting how many items they
+inspect over 20 rounds. /What is the level of monkey business after 20
+rounds of stuff-slinging simian shenanigans?/
+
+Your puzzle answer was =54253=.
+
+** --- Part Two ---
+You're worried you might not ever get your items back. So worried, in
+fact, that your relief that a monkey's inspection didn't damage an item
+/no longer causes your worry level to be divided by three/.
+
+Unfortunately, that relief was all that was keeping your worry levels
+from reaching /ridiculous levels/. You'll need to /find another way to
+keep your worry levels manageable/.
+
+At this rate, you might be putting up with these monkeys for a /very
+long time/ - possibly /=10000= rounds/!
+
+With these new rules, you can still figure out the monkey business after
+10000 rounds. Using the same example above:
+
+#+begin_example
+== After round 1 ==
+Monkey 0 inspected items 2 times.
+Monkey 1 inspected items 4 times.
+Monkey 2 inspected items 3 times.
+Monkey 3 inspected items 6 times.
+
+== After round 20 ==
+Monkey 0 inspected items 99 times.
+Monkey 1 inspected items 97 times.
+Monkey 2 inspected items 8 times.
+Monkey 3 inspected items 103 times.
+
+== After round 1000 ==
+Monkey 0 inspected items 5204 times.
+Monkey 1 inspected items 4792 times.
+Monkey 2 inspected items 199 times.
+Monkey 3 inspected items 5192 times.
+
+== After round 2000 ==
+Monkey 0 inspected items 10419 times.
+Monkey 1 inspected items 9577 times.
+Monkey 2 inspected items 392 times.
+Monkey 3 inspected items 10391 times.
+
+== After round 3000 ==
+Monkey 0 inspected items 15638 times.
+Monkey 1 inspected items 14358 times.
+Monkey 2 inspected items 587 times.
+Monkey 3 inspected items 15593 times.
+
+== After round 4000 ==
+Monkey 0 inspected items 20858 times.
+Monkey 1 inspected items 19138 times.
+Monkey 2 inspected items 780 times.
+Monkey 3 inspected items 20797 times.
+
+== After round 5000 ==
+Monkey 0 inspected items 26075 times.
+Monkey 1 inspected items 23921 times.
+Monkey 2 inspected items 974 times.
+Monkey 3 inspected items 26000 times.
+
+== After round 6000 ==
+Monkey 0 inspected items 31294 times.
+Monkey 1 inspected items 28702 times.
+Monkey 2 inspected items 1165 times.
+Monkey 3 inspected items 31204 times.
+
+== After round 7000 ==
+Monkey 0 inspected items 36508 times.
+Monkey 1 inspected items 33488 times.
+Monkey 2 inspected items 1360 times.
+Monkey 3 inspected items 36400 times.
+
+== After round 8000 ==
+Monkey 0 inspected items 41728 times.
+Monkey 1 inspected items 38268 times.
+Monkey 2 inspected items 1553 times.
+Monkey 3 inspected items 41606 times.
+
+== After round 9000 ==
+Monkey 0 inspected items 46945 times.
+Monkey 1 inspected items 43051 times.
+Monkey 2 inspected items 1746 times.
+Monkey 3 inspected items 46807 times.
+
+== After round 10000 ==
+Monkey 0 inspected items 52166 times.
+Monkey 1 inspected items 47830 times.
+Monkey 2 inspected items 1938 times.
+Monkey 3 inspected items 52013 times.
+#+end_example
+
+After 10000 rounds, the two most active monkeys inspected items 52166
+and 52013 times. Multiplying these together, the level of /monkey
+business/ in this situation is now =2713310158=.
+
+Worry levels are no longer divided by three after each item is
+inspected; you'll need to find another way to keep your worry levels
+manageable. Starting again from the initial state in your puzzle input,
+/what is the level of monkey business after 10000 rounds?/
+
+Your puzzle answer was =13119526120=.
+
+Both parts of this puzzle are complete! They provide two gold stars: **