2022/day 5 init

2022/day05/README.org

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+** --- Day 5: Supply Stacks ---
+The expedition can depart as soon as the final supplies have been
+unloaded from the ships. Supplies are stored in stacks of marked
+/crates/, but because the needed supplies are buried under many other
+crates, the crates need to be rearranged.
+
+The ship has a /giant cargo crane/ capable of moving crates between
+stacks. To ensure none of the crates get crushed or fall over, the crane
+operator will rearrange them in a series of carefully-planned steps.
+After the crates are rearranged, the desired crates will be at the top
+of each stack.
+
+The Elves don't want to interrupt the crane operator during this
+delicate procedure, but they forgot to ask her /which/ crate will end up
+where, and they want to be ready to unload them as soon as possible so
+they can embark.
+
+They do, however, have a drawing of the starting stacks of crates /and/
+the rearrangement procedure (your puzzle input). For example:
+
+#+begin_example
+    [D]
+[N] [C]
+[Z] [M] [P]
+ 1   2   3
+
+move 1 from 2 to 1
+move 3 from 1 to 3
+move 2 from 2 to 1
+move 1 from 1 to 2
+#+end_example
+
+In this example, there are three stacks of crates. Stack 1 contains two
+crates: crate =Z= is on the bottom, and crate =N= is on top. Stack 2
+contains three crates; from bottom to top, they are crates =M=, =C=, and
+=D=. Finally, stack 3 contains a single crate, =P=.
+
+Then, the rearrangement procedure is given. In each step of the
+procedure, a quantity of crates is moved from one stack to a different
+stack. In the first step of the above rearrangement procedure, one crate
+is moved from stack 2 to stack 1, resulting in this configuration:
+
+#+begin_example
+[D]
+[N] [C]
+[Z] [M] [P]
+ 1   2   3
+#+end_example
+
+In the second step, three crates are moved from stack 1 to stack 3.
+Crates are moved /one at a time/, so the first crate to be moved (=D=)
+ends up below the second and third crates:
+
+#+begin_example
+        [Z]
+        [N]
+    [C] [D]
+    [M] [P]
+ 1   2   3
+#+end_example
+
+Then, both crates are moved from stack 2 to stack 1. Again, because
+crates are moved /one at a time/, crate =C= ends up below crate =M=:
+
+#+begin_example
+        [Z]
+        [N]
+[M]     [D]
+[C]     [P]
+ 1   2   3
+#+end_example
+
+Finally, one crate is moved from stack 1 to stack 2:
+
+#+begin_example
+        [Z]
+        [N]
+        [D]
+[C] [M] [P]
+ 1   2   3
+#+end_example
+
+The Elves just need to know /which crate will end up on top of each
+stack/; in this example, the top crates are =C= in stack 1, =M= in stack
+2, and =Z= in stack 3, so you should combine these together and give the
+Elves the message =CMZ=.
+
+/After the rearrangement procedure completes, what crate ends up on top
+of each stack?/
+
+To begin, [[file:5/input][get your puzzle input]].