day 10 in under the wire

day10/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day10"
+version = "0.1.0"

day10/Cargo.toml

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+[package]
+name = "day10"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

day10/src/main.rs

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+use std::iter::*;
+use std::fs;
+use std::env;
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+struct Coord {x: i32, y: i32}
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+enum Dir {
+    North,
+    South,
+    West,
+    East
+}
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+struct Pipe {
+    a: Dir,
+    b: Dir
+}
+
+struct Grid<T: Copy> {
+    g: Vec<Vec<T>>
+}
+impl<T: Copy> Grid<T> {
+    fn get(&self, r: Coord) -> Option<T> {
+        if r.y < 0 || r.y >= self.g.len() as i32 {
+            return None;
+        }
+        if r.x < 0 || r.x >= self.g[0].len() as i32 {
+            return None;
+        }
+        Some(self.g[r.y as usize][r.x as usize])
+    }
+    fn set(&mut self, r: Coord, value: T) {
+        if r.y < 0 || r.y >= self.g.len() as i32 {
+            return ();
+        }
+        if r.x < 0 || r.x >= self.g[0].len() as i32 {
+            return ();
+        }
+        self.g[r.y as usize][r.x as usize] = value;
+    }
+}
+
+fn main() {
+    println!("Hello, AoC day 9!");
+
+    let args: Vec<String> = env::args().collect();
+    if args.len() != 2 {
+        println!("wrong number of arguments!");
+        std::process::exit(1);
+    }
+
+    let file_path = &args[1];
+
+    let contents = fs::read_to_string(file_path)
+        .expect("Should have been able to read the file");
+
+    let directions = vec![Dir::North, Dir::South, Dir::East, Dir::West];
+
+    let mut grid = Grid::<char> { g: Vec::new() };
+    let mut start = Coord { x: -1, y: -1};
+
+    // let's build that grid
+    for (y, line) in contents.lines().enumerate() {
+        let mut row = Vec::new();
+        for (x, c) in line.chars().enumerate() {
+            if c == 'S' {
+                start.x = x as i32;
+                start.y = y as i32;
+            }
+            row.push(c);
+        }
+        grid.g.push(row);
+    }
+
+    let mut starting_directions = Vec::new();
+
+    // now let's figure out what pipe the starting position should be
+    for direction in directions {
+
+        //figure out what a return pipe would look like
+        let ret = opposite(direction);
+        //step once in that direction
+        if let Some(next) = grid.get(step(start, direction)) {
+            println!("we're at {start:?}, looking {direction:?} at {next:?}");
+
+            if let Some(candidates) = connects(next) {
+                if candidates.0 == ret || candidates.1 == ret {
+                    starting_directions.push(direction);
+                }
+            }
+        }
+    }
+    let true_s = match (starting_directions[0], starting_directions[1]) {
+        (Dir::South, Dir::East) => 'F',
+        (Dir::East, Dir::South) => 'F',
+        (Dir::North, Dir::West) => 'J',
+        (Dir::West, Dir::North) => 'J',
+        (Dir::North, Dir::East) => 'L',
+        (Dir::East, Dir::North) => 'L',
+        (Dir::South, Dir::West) => '7',
+        (Dir::West, Dir::South) => '7',
+        (Dir::North, Dir::South) => '|',
+        (Dir::South, Dir::North) => '|',
+        (Dir::East, Dir::West) => '-',
+        (Dir::West, Dir::East) => '-',
+        _ => 'S'
+    };
+    grid.set(start, true_s);
+
+
+    let mut summing_field = Grid::<i32> { g: Vec::new() };
+    for _y in 0..grid.g.len() {
+        let mut new_row = Vec::new();
+        for _x in 0..grid.g[0].len() {
+            new_row.push(0);
+        }
+        summing_field.g.push(new_row);
+    }
+
+    // now let's walk around the path and count the steps, then divide by two
+    let mut r = start;
+    let mut facing = starting_directions[0];
+    let mut steps = 0;
+
+    while steps == 0 || r != start {
+        r = step(r, facing);
+        // we just stepped to the new r, frmo the old r, in the direction facing
+        let new_facing = turn(facing, grid.get(r).expect("We were pointed in this direction. It should be fine."));
+        for z in 0..r.x+1 {
+            summing_field.g[r.y as usize][z as usize] += match facing {
+                Dir::North => 1,
+                Dir::South => -1,
+                Dir::East => 0,
+                Dir::West => 0
+            };
+            summing_field.g[r.y as usize][z as usize] += match new_facing {
+                Dir::North => 1,
+                Dir::South => -1,
+                Dir::East => 0,
+                Dir::West => 0
+            };
+        }
+        facing = new_facing;
+        steps += 1;
+    }
+
+    let mut r = start;
+    let mut facing = starting_directions[0];
+    let mut steps = 0;
+
+    while steps == 0 || r != start {
+        r = step(r, facing);
+        // we just stepped to the new r, frmo the old r, in the direction facing
+        facing = turn(facing, grid.get(r).expect("We were pointed in this direction. It should be fine."));
+        summing_field.set(r, 0);
+        steps += 1;
+    }
+    println!("map:");
+    for row in grid.g {
+        println!("{row:?}");
+    }
+
+    let mut sum = 0;
+    println!("summing field:");
+    for row in summing_field.g {
+        println!("{row:?}");
+        for x in row {
+            sum += x;
+        }
+    }
+    sum = sum / 2;
+
+
+    println!("{steps} steps around the loop!");
+    let halfway = steps / 2;
+    println!("halfway is {halfway}!");
+
+    println!("behold, this is the sum of sums!: {sum}");
+
+
+}
+
+fn step(r: Coord, direction: Dir) -> Coord {
+    match direction {
+        Dir::North => Coord { x: r.x, y: r.y-1 },
+        Dir::South => Coord { x: r.x, y: r.y+1 },
+        Dir::West => Coord { x: r.x-1, y: r.y },
+        Dir::East => Coord { x: r.x+1, y: r.y },
+    }
+}
+
+fn turn(going: Dir, x: char) -> Dir {
+    match (going, x) {
+        (Dir::North,    'F') => Dir::East,
+        (Dir::West,     'F') => Dir::South,
+        (Dir::South,    'J') => Dir::West,
+        (Dir::East,     'J') => Dir::North,
+        (Dir::South,    'L') => Dir::East,
+        (Dir::West,     'L') => Dir::North,
+        (Dir::East,     '7') => Dir::South,
+        (Dir::North,    '7') => Dir::West,
+        (Dir::North,    '|') => Dir::North,
+        (Dir::South,    '|') => Dir::South,
+        (Dir::East,     '-') => Dir::East,
+        (Dir::West,     '-') => Dir::West,
+        (_, 'S') => Dir::North,
+        (_d, _c) => panic!("\"Just don't worry about it. This won't happen.\" -- Shoofle Dot Net")
+    }
+}
+
+fn connects(x: char) -> Option<(Dir, Dir)> {
+    match x {
+        'F' => Some((Dir::South, Dir::East)),
+        'J' => Some((Dir::North, Dir::West)),
+        'L' => Some((Dir::North, Dir::East)),
+        '7' => Some((Dir::South, Dir::West)),
+        '|' => Some((Dir::North, Dir::South)),
+        '-' => Some((Dir::East, Dir::West)),
+        _ => None
+    }
+}
+
+fn opposite(x: Dir) -> Dir {
+    match x {
+        Dir::North => Dir::South,
+        Dir::South => Dir::North,
+        Dir::East => Dir::West,
+        Dir::West => Dir::East,
+    }
+}

day10/target/.rustc_info.json

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+{"rustc_fingerprint":11672801278650259402,"outputs":{"4614504638168534921":{"success":true,"status":"","code":0,"stdout":"rustc 1.69.0 (84c898d65 2023-04-16)\nbinary: rustc\ncommit-hash: 84c898d65adf2f39a5a98507f1fe0ce10a2b8dbc\ncommit-date: 2023-04-16\nhost: x86_64-apple-darwin\nrelease: 1.69.0\nLLVM version: 15.0.7\n","stderr":""},"15729799797837862367":{"success":true,"status":"","code":0,"stdout":"___\nlib___.rlib\nlib___.dylib\nlib___.dylib\nlib___.a\nlib___.dylib\n/Users/shoofle/.rustup/toolchains/stable-x86_64-apple-darwin\noff\npacked\nunpacked\n___\ndebug_assertions\npanic=\"unwind\"\nproc_macro\ntarget_arch=\"x86_64\"\ntarget_endian=\"little\"\ntarget_env=\"\"\ntarget_family=\"unix\"\ntarget_feature=\"cmpxchg16b\"\ntarget_feature=\"fxsr\"\ntarget_feature=\"sse\"\ntarget_feature=\"sse2\"\ntarget_feature=\"sse3\"\ntarget_feature=\"ssse3\"\ntarget_has_atomic=\"128\"\ntarget_has_atomic=\"16\"\ntarget_has_atomic=\"32\"\ntarget_has_atomic=\"64\"\ntarget_has_atomic=\"8\"\ntarget_has_atomic=\"ptr\"\ntarget_os=\"macos\"\ntarget_pointer_width=\"64\"\ntarget_vendor=\"apple\"\nunix\n","stderr":""}},"successes":{}}

day10/target/CACHEDIR.TAG

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+Signature: 8a477f597d28d172789f06886806bc55
+# This file is a cache directory tag created by cargo.
+# For information about cache directory tags see https://bford.info/cachedir/

day10/target/debug/.fingerprint/day10-ef99a7eb2ce83b6e/bin-day10

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+dd078a3fb23733e6

day10/target/debug/.fingerprint/day10-ef99a7eb2ce83b6e/bin-day10.json

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+{"rustc":3659767333214291318,"features":"[]","target":14519807996045575918,"profile":11736316127369858332,"path":1684066648322511884,"deps":[],"local":[{"CheckDepInfo":{"dep_info":"debug/.fingerprint/day10-ef99a7eb2ce83b6e/dep-bin-day10"}}],"rustflags":[],"metadata":7797948686568424061,"config":2202906307356721367,"compile_kind":0}

day10/target/debug/.fingerprint/day10-ef99a7eb2ce83b6e/invoked.timestamp

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+This file has an mtime of when this was started.

day10/target/debug/day10.d

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+/Users/shoofle/Projects/aoc_2023/day10/target/debug/day10: /Users/shoofle/Projects/aoc_2023/day10/src/main.rs

day10/target/debug/deps/day10-ef99a7eb2ce83b6e.d

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+/Users/shoofle/Projects/aoc_2023/day10/target/debug/deps/day10-ef99a7eb2ce83b6e: src/main.rs
+
+/Users/shoofle/Projects/aoc_2023/day10/target/debug/deps/day10-ef99a7eb2ce83b6e.d: src/main.rs
+
+src/main.rs: