complete day 5

4 files changed, 806 insertions, 0 deletions

diff --git a/day05a/Cargo.toml b/day05a/Cargo.toml
new file mode 100644
index 0000000..4ff4967
--- /dev/null
+++ b/day05a/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "day05a"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+clap = { version = "3.2.20", features = ["derive"] }
+nom = "7.1.1"
+itertools = "0.10.5"
diff --git a/day05a/examples/input.txt b/day05a/examples/input.txt
new file mode 100644
index 0000000..ca57552
--- /dev/null
+++ b/day05a/examples/input.txt
@@ -0,0 +1,513 @@
+[C]         [S] [H]                
+[F] [B]     [C] [S]     [W]        
+[B] [W]     [W] [M] [S] [B]        
+[L] [H] [G] [L] [P] [F] [Q]        
+[D] [P] [J] [F] [T] [G] [M] [T]    
+[P] [G] [B] [N] [L] [W] [P] [W] [R]
+[Z] [V] [W] [J] [J] [C] [T] [S] [C]
+[S] [N] [F] [G] [W] [B] [H] [F] [N]
+ 1   2   3   4   5   6   7   8   9 
+
+move 2 from 5 to 9
+move 3 from 1 to 7
+move 2 from 3 to 9
+move 6 from 9 to 5
+move 2 from 3 to 8
+move 9 from 7 to 8
+move 15 from 8 to 9
+move 3 from 1 to 6
+move 6 from 4 to 2
+move 6 from 5 to 6
+move 1 from 4 to 2
+move 14 from 6 to 2
+move 2 from 1 to 5
+move 1 from 7 to 3
+move 1 from 4 to 8
+move 2 from 5 to 6
+move 25 from 2 to 4
+move 2 from 6 to 4
+move 1 from 8 to 1
+move 2 from 9 to 1
+move 1 from 6 to 1
+move 2 from 1 to 7
+move 1 from 7 to 3
+move 2 from 1 to 8
+move 1 from 2 to 6
+move 1 from 3 to 8
+move 4 from 5 to 6
+move 1 from 5 to 3
+move 1 from 9 to 6
+move 2 from 3 to 4
+move 1 from 2 to 6
+move 12 from 9 to 7
+move 1 from 9 to 1
+move 1 from 5 to 8
+move 1 from 3 to 8
+move 28 from 4 to 5
+move 1 from 4 to 3
+move 1 from 2 to 6
+move 1 from 3 to 9
+move 12 from 7 to 2
+move 1 from 9 to 6
+move 6 from 6 to 4
+move 1 from 7 to 4
+move 1 from 1 to 2
+move 28 from 5 to 1
+move 2 from 2 to 8
+move 3 from 8 to 2
+move 7 from 4 to 1
+move 4 from 8 to 6
+move 9 from 2 to 8
+move 7 from 6 to 5
+move 3 from 5 to 9
+move 1 from 9 to 7
+move 1 from 7 to 1
+move 5 from 8 to 4
+move 4 from 1 to 9
+move 6 from 9 to 4
+move 5 from 1 to 5
+move 5 from 2 to 3
+move 4 from 8 to 2
+move 5 from 1 to 4
+move 4 from 5 to 9
+move 9 from 4 to 9
+move 10 from 9 to 8
+move 1 from 9 to 1
+move 2 from 2 to 8
+move 4 from 3 to 8
+move 1 from 2 to 3
+move 2 from 9 to 2
+move 1 from 2 to 6
+move 4 from 4 to 3
+move 3 from 5 to 1
+move 12 from 1 to 4
+move 1 from 5 to 3
+move 1 from 5 to 3
+move 5 from 8 to 5
+move 7 from 8 to 5
+move 8 from 3 to 4
+move 1 from 5 to 1
+move 1 from 6 to 7
+move 2 from 1 to 6
+move 8 from 5 to 9
+move 2 from 5 to 1
+move 9 from 1 to 4
+move 20 from 4 to 2
+move 1 from 5 to 2
+move 4 from 4 to 2
+move 5 from 9 to 2
+move 2 from 8 to 9
+move 23 from 2 to 4
+move 2 from 2 to 5
+move 5 from 1 to 2
+move 28 from 4 to 3
+move 2 from 8 to 1
+move 2 from 5 to 7
+move 1 from 6 to 9
+move 1 from 4 to 8
+move 1 from 8 to 9
+move 1 from 4 to 6
+move 2 from 7 to 2
+move 13 from 3 to 4
+move 5 from 9 to 7
+move 1 from 9 to 6
+move 14 from 2 to 6
+move 1 from 4 to 1
+move 10 from 3 to 2
+move 1 from 6 to 9
+move 2 from 3 to 2
+move 3 from 1 to 9
+move 1 from 3 to 5
+move 3 from 9 to 3
+move 6 from 7 to 4
+move 1 from 9 to 4
+move 1 from 9 to 2
+move 1 from 5 to 3
+move 5 from 3 to 1
+move 17 from 4 to 7
+move 2 from 2 to 8
+move 1 from 3 to 9
+move 1 from 8 to 2
+move 1 from 9 to 6
+move 4 from 6 to 2
+move 10 from 6 to 5
+move 4 from 1 to 5
+move 15 from 2 to 9
+move 1 from 8 to 6
+move 1 from 2 to 8
+move 6 from 9 to 2
+move 3 from 4 to 8
+move 11 from 7 to 1
+move 6 from 9 to 6
+move 1 from 6 to 2
+move 3 from 9 to 3
+move 6 from 2 to 7
+move 6 from 7 to 8
+move 7 from 1 to 9
+move 4 from 1 to 6
+move 2 from 1 to 2
+move 4 from 6 to 7
+move 1 from 2 to 9
+move 1 from 2 to 3
+move 1 from 2 to 1
+move 6 from 8 to 4
+move 2 from 6 to 7
+move 13 from 5 to 9
+move 1 from 5 to 4
+move 3 from 4 to 7
+move 1 from 1 to 7
+move 14 from 9 to 2
+move 2 from 9 to 3
+move 3 from 8 to 5
+move 4 from 3 to 4
+move 8 from 4 to 1
+move 7 from 1 to 9
+move 5 from 6 to 9
+move 4 from 9 to 2
+move 1 from 1 to 9
+move 17 from 2 to 4
+move 1 from 6 to 3
+move 4 from 7 to 5
+move 5 from 7 to 5
+move 1 from 6 to 4
+move 1 from 8 to 3
+move 5 from 7 to 1
+move 2 from 7 to 6
+move 2 from 3 to 6
+move 1 from 2 to 9
+move 7 from 9 to 6
+move 2 from 3 to 7
+move 8 from 6 to 4
+move 3 from 9 to 2
+move 1 from 6 to 4
+move 26 from 4 to 8
+move 2 from 7 to 8
+move 5 from 5 to 9
+move 2 from 6 to 7
+move 4 from 9 to 1
+move 2 from 7 to 5
+move 14 from 8 to 6
+move 3 from 2 to 8
+move 3 from 6 to 8
+move 3 from 6 to 1
+move 10 from 8 to 4
+move 5 from 9 to 4
+move 3 from 8 to 5
+move 1 from 8 to 2
+move 12 from 4 to 8
+move 1 from 9 to 3
+move 6 from 6 to 4
+move 6 from 8 to 2
+move 1 from 3 to 8
+move 1 from 8 to 4
+move 10 from 1 to 9
+move 2 from 1 to 3
+move 7 from 4 to 9
+move 1 from 2 to 1
+move 11 from 8 to 9
+move 1 from 3 to 9
+move 2 from 2 to 7
+move 1 from 3 to 6
+move 2 from 7 to 9
+move 2 from 4 to 6
+move 4 from 6 to 4
+move 2 from 2 to 8
+move 2 from 8 to 4
+move 1 from 1 to 7
+move 2 from 2 to 8
+move 9 from 5 to 2
+move 3 from 5 to 9
+move 1 from 8 to 3
+move 30 from 9 to 7
+move 1 from 6 to 2
+move 7 from 4 to 8
+move 13 from 7 to 2
+move 8 from 7 to 4
+move 2 from 4 to 8
+move 8 from 8 to 1
+move 1 from 8 to 3
+move 2 from 8 to 9
+move 1 from 3 to 7
+move 5 from 7 to 6
+move 1 from 3 to 1
+move 7 from 4 to 8
+move 20 from 2 to 6
+move 2 from 2 to 7
+move 1 from 9 to 5
+move 4 from 7 to 6
+move 3 from 7 to 8
+move 1 from 7 to 2
+move 7 from 8 to 6
+move 3 from 6 to 7
+move 4 from 9 to 1
+move 1 from 2 to 6
+move 1 from 9 to 7
+move 1 from 2 to 8
+move 1 from 7 to 6
+move 3 from 6 to 3
+move 4 from 8 to 1
+move 8 from 6 to 4
+move 3 from 7 to 2
+move 1 from 3 to 2
+move 1 from 4 to 5
+move 2 from 3 to 5
+move 1 from 4 to 6
+move 4 from 1 to 5
+move 4 from 2 to 9
+move 2 from 1 to 6
+move 4 from 9 to 2
+move 3 from 2 to 8
+move 2 from 8 to 4
+move 13 from 6 to 1
+move 4 from 5 to 2
+move 14 from 6 to 3
+move 1 from 2 to 7
+move 2 from 2 to 4
+move 1 from 8 to 6
+move 1 from 6 to 3
+move 1 from 7 to 4
+move 1 from 2 to 3
+move 1 from 2 to 6
+move 11 from 4 to 6
+move 2 from 5 to 4
+move 1 from 5 to 6
+move 12 from 3 to 6
+move 1 from 3 to 7
+move 1 from 5 to 7
+move 3 from 3 to 6
+move 2 from 7 to 5
+move 2 from 5 to 2
+move 8 from 6 to 7
+move 24 from 1 to 3
+move 1 from 4 to 6
+move 10 from 3 to 1
+move 6 from 1 to 8
+move 1 from 6 to 3
+move 1 from 4 to 2
+move 1 from 3 to 1
+move 2 from 2 to 1
+move 1 from 7 to 6
+move 2 from 7 to 5
+move 4 from 3 to 7
+move 1 from 2 to 3
+move 6 from 1 to 6
+move 3 from 7 to 5
+move 4 from 7 to 8
+move 1 from 1 to 2
+move 1 from 2 to 7
+move 8 from 3 to 4
+move 3 from 4 to 7
+move 6 from 8 to 6
+move 2 from 3 to 2
+move 1 from 3 to 9
+move 5 from 5 to 1
+move 2 from 8 to 2
+move 1 from 9 to 2
+move 4 from 1 to 3
+move 3 from 2 to 9
+move 1 from 1 to 2
+move 2 from 9 to 7
+move 2 from 2 to 9
+move 8 from 7 to 5
+move 33 from 6 to 5
+move 20 from 5 to 9
+move 21 from 5 to 7
+move 17 from 7 to 6
+move 10 from 6 to 9
+move 5 from 4 to 7
+move 2 from 3 to 9
+move 1 from 2 to 3
+move 2 from 7 to 3
+move 3 from 9 to 5
+move 23 from 9 to 7
+move 8 from 9 to 6
+move 1 from 9 to 1
+move 1 from 5 to 3
+move 1 from 8 to 9
+move 5 from 6 to 8
+move 1 from 9 to 6
+move 18 from 7 to 2
+move 6 from 7 to 4
+move 6 from 4 to 8
+move 5 from 7 to 4
+move 6 from 6 to 3
+move 1 from 4 to 2
+move 10 from 2 to 1
+move 1 from 2 to 4
+move 7 from 1 to 6
+move 1 from 7 to 1
+move 11 from 6 to 2
+move 1 from 6 to 8
+move 12 from 3 to 1
+move 8 from 1 to 8
+move 2 from 5 to 2
+move 12 from 8 to 6
+move 15 from 2 to 4
+move 7 from 4 to 5
+move 4 from 5 to 9
+move 4 from 9 to 4
+move 5 from 4 to 6
+move 2 from 5 to 2
+move 1 from 2 to 5
+move 2 from 5 to 4
+move 2 from 1 to 3
+move 4 from 1 to 5
+move 2 from 8 to 4
+move 5 from 2 to 9
+move 17 from 6 to 8
+move 1 from 3 to 2
+move 2 from 5 to 4
+move 1 from 3 to 8
+move 1 from 1 to 6
+move 2 from 5 to 6
+move 3 from 9 to 5
+move 1 from 5 to 1
+move 3 from 1 to 8
+move 26 from 8 to 4
+move 1 from 5 to 3
+move 3 from 2 to 7
+move 1 from 5 to 7
+move 21 from 4 to 9
+move 19 from 4 to 5
+move 3 from 4 to 3
+move 2 from 7 to 5
+move 1 from 8 to 2
+move 1 from 6 to 2
+move 1 from 8 to 9
+move 1 from 6 to 7
+move 1 from 2 to 4
+move 1 from 4 to 7
+move 1 from 2 to 7
+move 1 from 7 to 1
+move 1 from 1 to 6
+move 1 from 3 to 5
+move 2 from 6 to 3
+move 13 from 5 to 8
+move 1 from 4 to 2
+move 3 from 5 to 4
+move 5 from 5 to 4
+move 5 from 8 to 9
+move 9 from 9 to 3
+move 2 from 7 to 1
+move 6 from 4 to 2
+move 8 from 9 to 4
+move 1 from 2 to 7
+move 12 from 9 to 8
+move 1 from 4 to 2
+move 3 from 7 to 3
+move 11 from 8 to 5
+move 5 from 8 to 6
+move 3 from 6 to 5
+move 2 from 4 to 1
+move 13 from 5 to 3
+move 1 from 1 to 7
+move 2 from 1 to 8
+move 3 from 4 to 9
+move 1 from 1 to 7
+move 1 from 2 to 4
+move 2 from 7 to 3
+move 1 from 5 to 3
+move 4 from 4 to 2
+move 1 from 4 to 9
+move 30 from 3 to 2
+move 1 from 9 to 7
+move 6 from 8 to 6
+move 1 from 7 to 6
+move 1 from 5 to 1
+move 1 from 3 to 5
+move 30 from 2 to 3
+move 1 from 1 to 9
+move 2 from 9 to 2
+move 9 from 6 to 9
+move 2 from 2 to 9
+move 1 from 5 to 1
+move 5 from 9 to 7
+move 8 from 2 to 5
+move 1 from 1 to 9
+move 3 from 9 to 1
+move 5 from 3 to 6
+move 8 from 5 to 9
+move 13 from 3 to 9
+move 3 from 1 to 7
+move 5 from 7 to 9
+move 17 from 9 to 6
+move 1 from 7 to 6
+move 6 from 3 to 9
+move 1 from 2 to 1
+move 2 from 7 to 1
+move 1 from 2 to 5
+move 21 from 9 to 2
+move 4 from 3 to 6
+move 6 from 6 to 5
+move 7 from 5 to 9
+move 2 from 3 to 8
+move 3 from 1 to 3
+move 4 from 6 to 5
+move 1 from 8 to 1
+move 1 from 8 to 2
+move 4 from 5 to 2
+move 4 from 9 to 1
+move 4 from 3 to 5
+move 2 from 1 to 7
+move 1 from 7 to 4
+move 3 from 9 to 5
+move 25 from 2 to 9
+move 18 from 9 to 1
+move 1 from 4 to 5
+move 1 from 3 to 8
+move 4 from 5 to 6
+move 2 from 9 to 3
+move 17 from 1 to 5
+move 1 from 2 to 7
+move 2 from 3 to 5
+move 3 from 1 to 8
+move 5 from 9 to 2
+move 4 from 8 to 9
+move 12 from 5 to 2
+move 1 from 1 to 8
+move 3 from 9 to 5
+move 1 from 8 to 2
+move 2 from 7 to 2
+move 1 from 9 to 5
+move 9 from 5 to 2
+move 6 from 6 to 2
+move 15 from 6 to 2
+move 5 from 5 to 9
+move 1 from 5 to 9
+move 3 from 9 to 2
+move 3 from 9 to 1
+move 1 from 1 to 9
+move 1 from 9 to 1
+move 19 from 2 to 8
+move 2 from 1 to 9
+move 33 from 2 to 6
+move 4 from 6 to 4
+move 1 from 2 to 6
+move 1 from 9 to 8
+move 3 from 4 to 8
+move 18 from 8 to 3
+move 1 from 4 to 9
+move 10 from 3 to 9
+move 1 from 1 to 4
+move 24 from 6 to 3
+move 1 from 4 to 3
+move 2 from 8 to 7
+move 8 from 9 to 3
+move 5 from 6 to 7
+move 35 from 3 to 2
+move 7 from 7 to 1
+move 3 from 1 to 3
+move 33 from 2 to 6
+move 6 from 3 to 7
+move 5 from 7 to 3
+move 1 from 1 to 4
+move 1 from 7 to 8
+move 1 from 4 to 8
+move 1 from 3 to 2
+move 30 from 6 to 5
+move 2 from 1 to 6
+move 5 from 8 to 1
+move 1 from 9 to 2
+move 2 from 6 to 4
+move 4 from 1 to 7
+move 21 from 5 to 8
diff --git a/day05a/examples/test.txt b/day05a/examples/test.txt
new file mode 100644
index 0000000..84933bb
--- /dev/null
+++ b/day05a/examples/test.txt
@@ -0,0 +1,9 @@
+    [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
diff --git a/day05a/src/main.rs b/day05a/src/main.rs
new file mode 100644
index 0000000..ac7a6d7
--- /dev/null
+++ b/day05a/src/main.rs
@@ -0,0 +1,273 @@
+/// --- 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:
+///
+///     [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
+///
+/// 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:
+///
+/// [D]        
+/// [N] [C]    
+/// [Z] [M] [P]
+///  1   2   3
+///
+/// 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:
+///
+///         [Z]
+///         [N]
+///     [C] [D]
+///     [M] [P]
+///  1   2   3
+///
+/// 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:
+///
+///         [Z]
+///         [N]
+/// [M]     [D]
+/// [C]     [P]
+///  1   2   3
+///
+/// Finally, one crate is moved from stack 1 to stack 2:
+///
+///         [Z]
+///         [N]
+///         [D]
+/// [C] [M] [P]
+///  1   2   3
+///
+/// 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?
+use clap::Parser;
+use itertools::Itertools;
+use nom::branch::alt;
+use nom::bytes::complete::tag;
+use nom::character::complete::{alpha1, digit1, multispace1};
+use nom::combinator::{map, opt, peek};
+use nom::error::{ErrorKind as NomErrorKind, ParseError};
+use nom::multi::{many1, many1_count};
+use nom::sequence::{delimited, preceded, terminated};
+use nom::IResult;
+
+use std::fs::File;
+use std::io::prelude::*;
+use std::io::BufReader;
+use std::iter::*;
+use std::path::PathBuf;
+
+pub type Input<'a> = &'a str;
+pub type Result<'a, T> = IResult<Input<'a>, T, Error<Input<'a>>>;
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum ErrorKind {
+    Nom(NomErrorKind),
+    Context(&'static str),
+    Custom(String),
+}
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct Error<I> {
+    pub errors: Vec<(I, ErrorKind)>,
+}
+
+impl<I> ParseError<I> for Error<I> {
+    fn from_error_kind(input: I, kind: NomErrorKind) -> Self {
+        let errors = vec![(input, ErrorKind::Nom(kind))];
+        Self { errors }
+    }
+
+    fn append(input: I, kind: NomErrorKind, mut other: Self) -> Self {
+        other.errors.push((input, ErrorKind::Nom(kind)));
+        other
+    }
+}
+
+const FILEPATH: &'static str = "examples/input.txt";
+
+#[derive(Parser, Debug)]
+#[clap(author, version, about, long_about = None)]
+struct Cli {
+    #[clap(short, long, default_value = FILEPATH)]
+    file: PathBuf,
+}
+
+#[derive(Debug, Clone)]
+struct Supplies(Vec<Vec<char>>);
+
+#[derive(Debug, Clone)]
+struct Order {
+    from: usize,
+    to: usize,
+    amount: usize,
+}
+
+#[derive(Debug, Clone)]
+enum LineKind {
+    Axis(usize),
+    Crates(Vec<char>),
+}
+
+fn parse_digit(input: &str) -> Result<char> {
+    map(preceded(multispace1, digit1), |s: &str| {
+        s.chars().next().unwrap()
+    })(input)
+}
+
+fn parse_crate(input: &str) -> Result<char> {
+    map(delimited(tag("["), alpha1, tag("]")), |s: &str| {
+        s.chars().next().unwrap()
+    })(input)
+}
+
+fn parse_crate_or_empty(input: &str) -> Result<char> {
+    terminated(alt((map(tag("   "), |_| ' '), parse_crate)), opt(tag(" ")))(input)
+}
+
+fn parse_line(input: &str) -> Result<LineKind> {
+    let res = peek(parse_digit)(input);
+    if res.is_ok() {
+        map(many1_count(parse_digit), |len| LineKind::Axis(len))(input)
+    } else {
+        map(many1(parse_crate_or_empty), |v| LineKind::Crates(v))(input)
+    }
+}
+
+impl Supplies {
+    fn new() -> Self {
+        Self(Vec::<Vec<char>>::new())
+    }
+
+    fn idx_to_internal(idx: usize) -> usize {
+        idx - 1
+    }
+
+    fn initialize(&mut self, input: Vec<LineKind>) {
+        let axis = &input[input.len() - 1];
+        let LineKind::Axis(len) = axis else {
+            panic!();
+        };
+        self.resize(*len);
+
+        let _ = input
+            .into_iter()
+            .rev()
+            .skip(1)
+            .map(|x| match x {
+                LineKind::Crates(v) => v,
+                _ => panic!(),
+            })
+            .map(|vc| {
+                vc.into_iter()
+                    .zip(1usize..)
+                    .filter(|(c, _)| *c != ' ')
+                    .collect_vec()
+            })
+            .flatten()
+            .scan(self, |state, (c, idx)| {
+                state.push(idx, c);
+                Some(())
+            })
+            .last();
+    }
+
+    fn pop(&mut self, idx: usize) -> char {
+        self.0[Self::idx_to_internal(idx)].pop().unwrap()
+    }
+
+    fn peek(&self, idx: usize) -> char {
+        self.0[Self::idx_to_internal(idx)][self.0[Self::idx_to_internal(idx)].len() - 1]
+    }
+
+    fn push(&mut self, idx: usize, letter: char) {
+        self.0[Self::idx_to_internal(idx)].push(letter)
+    }
+
+    fn resize(&mut self, len: usize) {
+        self.0.resize(len, Vec::<char>::new())
+    }
+
+    fn top_chars(&self) -> String {
+        (0..self.0.len())
+            .map(|idx| self.peek(idx + 1).to_string())
+            .join("")
+    }
+
+    fn transfer(&mut self, order: Order) {
+        for _ in 0..order.amount {
+            let v = self.pop(order.from);
+            self.push(order.to, v);
+        }
+    }
+}
+
+fn main() {
+    let args = Cli::parse();
+
+    let file = File::open(&args.file).unwrap();
+    let reader = BufReader::new(file);
+
+    let init = reader
+        .lines()
+        .map(|l| l.unwrap())
+        .take_while(|l| !l.is_empty())
+        .map(|l| parse_line(l.as_str()).unwrap().1)
+        .collect_vec();
+
+    let mut supplies = Supplies::new();
+    supplies.initialize(init);
+
+    let file = File::open(&args.file).unwrap();
+    let reader = BufReader::new(file);
+    let _ = reader
+        .lines()
+        .map(|l| l.unwrap())
+        .skip_while(|l| !l.contains("move"))
+        .map(|l| {
+            let sp = l.split_whitespace().collect_vec();
+            Order {
+                from: sp[3].parse::<usize>().unwrap(),
+                to: sp[5].parse::<usize>().unwrap(),
+                amount: sp[1].parse::<usize>().unwrap(),
+            }
+        })
+        .scan(&mut supplies, |state, order| {
+            state.transfer(order);
+            Some(())
+        })
+        .last();
+
+    println!("{}", supplies.top_chars());
+}