day 12

Cargo.toml

@@ -12,4 +12,5 @@ members = [
     "day9",
     "day10",
     "day11",
+    "day12",
 ]

day12/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "day12"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+petgraph = "0.6.2"

day12/input.txt

@@ -0,0 +1,41 @@
+abaaacccccccccaaaaaaccccccccccccccccaacccccccccccaacaaaaaaaaaaaaaaaaaccaaaaacccaaaaccccccccccccccccccccccccccccccccccccccccccccccccccccccccaaaaa
+abaaacccccccccaaaaaacccccccccccccccaaaaccccccccccaaaaaaaacaaaaaaaaaaaccaaaaaaccaaaacccccccccccccccccccccccccccccccccccccccccccccccccccccccaaaaaa
+abaaaccccccccccaaaaacccccccccccccccaaaacccccccccccaaaaacccaaaaaaaaaacccaaaaaacccaaccccccccccccccaaaaacccccccccccccccccccccccccccccccccccccaaaaaa
+abccccaaccccccaaaaacccccccccaaaaaccaaaaccccccccccccaaaaacaaaaaaaaacccccaaaaaccccccccccccccccccccaaaaacccccccccccccccccaaaccccaaaccccccccccaaacaa
+abcccaaaacccccaaaaacccccccccaaaaacccccccccccccccccaaacaaaaaaaaaacccccccaaaaacccccccccccccccccccaaaaaacccccccccccccccccaaaaccaaaaccccccccccccccaa
+abcccaaaaacacccccccccccccccaaaaaaccccccccccccccccccaaccaaaaacaaaaccccccccccccccccccccccccccccccaaaaaaccccccccccccccccccaaaaaaaacccccccccccccccaa
+abaaaaaaaaaacccccccccccccccaaaaaaccccccccccccccccccccccaaaacccaaaccccccccccccccccccccccccccccccaaaaaacccccccccccccccciiiiijaaaaccccccccccccccccc
+abaaaaaaaaaacccccccccccccccaaaaaacccccccccccccccccccccccccccccaaacccccccccccccccccccccccccccccccaaaccccccccccccccccciiiiiijjjaccccccccaaaccccccc
+abccaaaaaaccccccccccccccccccaaaccccccccccccccccccccccccccccccccacccccccccccaacccccccccccccccccccccccccccccccccccccciiiiioijjjjaaccccccaaaaaacccc
+abccaaaaaacccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccaaaaaacccccccccccccccccccccccccccccccccccciiinnooojjjjjaaccaaaaaaaacccc
+abccaaaaaacccccccccccccccccccccccccccccccccccccaacccccaacccccccccccccccccaaaaaacccccccccccccccccccccccccccaaaccccciiinnnoooojjjjjjkkkaaaaaaacccc
+abcaaaaaaaaccccccccccccccccccccccccccccccccccccaaaccaaaaaaccccaaacccccccccaaaacccccccccccccccccccccccccccccaaaaccciiinnnouooojjjjkkkkkaaaaaccccc
+abccaccccccccccccccccccaaccccccaccccccccccccaaaaaaaaaaaaaacccaaaacccccccccaaaacccccccccccccccccccccccccccaaaaaacchhinnnttuuooooookkkkkkkaaaccccc
+abccccccccccccccccccaacaaaccccaaaaaaaaccccccaaaaaaaacaaaaacccaaaacccccccccaccacccccccccccccccccccccccccccaaaaacchhhhnntttuuuooooppppkkkkcaaacccc
+abccccccccaaacccccccaaaaaccccccaaaaaaccccccccaaaaaacaaaaaccccaaaaccccccccccccccccccccccccccccaccccccccccccaaaaahhhhnnntttxuuuooppppppkkkcccccccc
+abccccccccaaaacccccccaaaaaaccccaaaaaaccaaacccaaaaaacaaaaaccccccccccccccaaccccccccccccccaaaaaaaacccccccccccaachhhhhnnnntttxxuuuuuuuupppkkkccccccc
+abccccccccaaaacccccaaaaaaaacccaaaaaaaacaaacacaaaaaaccccccccccccccccccccaacccccccccccccccaaaaaacccccccccccccchhhhmnnnntttxxxxuuuuuuupppkkcccccccc
+abacccccccaaaacccccaaaaacaaccaaaaaaaaaaaaaaaaaaccaacccccccccccccccccaaaaaaaaccccccccccccaaaaaaccccccccccccchhhhmmmntttttxxxxuyyyuvvpppklcccccccc
+abacccccccccccccccccacaaaccaaaaaaaaaaaaaaaaaaaccccccccccccccccccccccaaaaaaaacccccccccccaaaaaaaaccccccccccccgghmmmtttttxxxxxxyyyyvvvpplllcccccccc
+abaccccccccaacccccccccaaaccaaaaaaaacaaaaaaaaaaccccccccccccccccccccccccaaaaccccccccccccaaaaaaaaaaccccccaccccgggmmmtttxxxxxxxyyyyyvvppplllcccccccc
+SbaaaccccccaaacaaaccccccccaaaaaaaaacaaaaaaaaacccccccccccccccccccccccccaaaaacccccccccccaaaaaaaaaaaaacaaaccaagggmmmtttxxxEzzzzyyyvvppplllccccccccc
+abaacccccccaaaaaaacccccccaaaaaaacaaccaaaaaaaccccccccccccccaaaccccccccaaaaaacccccccccccacacaaacccaaaaaaacaaagggmmmsssxxxxxyyyyyvvvqqqlllccccccccc
+abaccccccccaaaaaaccacccaaaaaaaaacccccccaaaaaaccccccccccccaaaaccccccccaaccaacccccccccccccccaaaccccaaaaaaccaagggmmmssssxxwwyyyyyyvvqqqlllccccccccc
+abaccccccaaaaaaaaccaacaaaccaaaaaacccccaaaaaaaccccccccccccaaaaccccccccccaacccccccccccccccccaacccccaaaaaaaaaaggggmmmssssswwyywyyyyvvqqlllccccccccc
+abaccccccaaaaaaaaacaaaaacccaaaaaacccccaaacaaaccccccccccccaaaaccccccccaaaaaaccccccccccccaacccccccaaaaaaaaaaaaggggmmmossswwyywwyyvvvqqqllccccccccc
+abcccccccaaaaaaaaaacaaaaaacaaccccccccaaacccccccccccccccccccccccccccccaaaaaaccccccccccccaaaaacccaaaaaaaaaaaaaaggggoooosswwywwwwvvvvqqqmlccccccccc
+abccccccccccaaacaaaaaaaaaacccccccccccaaacaccccccccccccccccccccccccccccaaaaccccccccccccaaaaaccccaaacaaacccaaacagggfooosswwwwwrvvvvqqqqmmccccccccc
+abccccccccccaaacccaaaaaaaacccccccccaacaaaaacccccccccccccccccccccccccccaaaaccccccccccccaaaaaacccccccaaacccaaccccfffooosswwwwrrrrrqqqqqmmccccccccc
+abccccccccccaacccccccaaccccccccccccaaaaaaaacccccccccccccaaccccccccccccaccaccccccccccccccaaaacccccccaacccccccccccfffoossrwrrrrrrrqqqqmmmccccccccc
+abccaaaccccccccccccccaacccccccccccccaaaaaccccccccccccaacaacccccccaaaaacccccccccccccccccaacccccccccccccccccccccccfffoossrrrrrnnnmqqmmmmmccccccccc
+abcaaaaccccccccccccccccccccccccccccccaaaaacccccccccccaaaaacccccccaaaaacccaaaccccccccccccccccccccccccccccccccccccfffooorrrrrnnnnmmmmmmmccccaacccc
+abcaaaacccccccccccccccccccccccccccccaaacaaccccacccccccaaaaaaccccaaaaaaccccaaaccacccccccccccccccccccccccccccccccccffoooonnnnnnnnmmmmmmccccaaacccc
+abccaaacccccccccccccccccccccaaaaaccccaaccccaaaacccccaaaaaaaaccccaaaaaaccccaaaaaaaccccccccccccccccaccaccccccccccccfffooonnnnnnddddddddcccaaaccccc
+abccccccccccccccccccccccccccaaaaaccccccccccaaaaaacccaaaaacaacccaaaaaaaccaaaaaaaacccccccccccccccccaaaaccccccccccccfffeonnnnneddddddddddcaaacccccc
+abccccccccccaaaccccccccccccaaaaaacccccccccccaaaacccccacaaacccccaacaacccaaaaaaaaacccccccccccccccccaaaacccccccccccccffeeeeeeeeddddddddcccaaacccccc
+abcccccccccaaaaccccacccccccaaaaaaccccccccccaaaaacccccccaaaacccaaacaccccaaaaaaaaaccccccccccccccccaaaaaaccccccccccccceeeeeeeeedacccccccccccccccccc
+abaccccccccaaaaccccaaacaaacaaaaaaccccccccccaacaaccccccccaaaacaaaacaaacaaaaaaaaaacccccccccccccaacaaaaaacccccccccccccceeeeeeeaaacccccccccccccccaaa
+abaaacccccccaaaccccaaaaaaaccaaaccccccccaaacccccccccccccccaaaaaaaacaaaaaaaaaaaaaaacacaaccaaacaaacccaacccccccccccccccccaacccaaaacccccccccccccccaaa
+abaaaccccccccccccccaaaaaaccccccccccccccaaacccccccccccccccaaaaaaaccaaaaaaccaacccaccaaaaccaaaaaaaccccccccaaccccccccccccccccccaaacccccccccccccccaaa
+abaaccccccccccccccaaaaaaacccccccccccaaaaaaaaccccccccccccccaaaaaaaaaaaaaacaaaccccccaaaaaccaaaaaaccccccaaaaccccccccccccccccccaaaccccccccccccaaaaaa
+abaaaccccccccccccaaaaaaaaaacccccccccaaaaaaaacccccccccccaaaaaaaaaaaaaaaaaaacccccccaaaaaacaaaaaaaaaccccaaaaaacccccccccccccccccccccccccccccccaaaaaa

day12/sample_input.txt

@@ -0,0 +1,5 @@
+Sabqponm
+abcryxxl
+accszExk
+acctuvwj
+abdefghi

day12/src/main.rs

@@ -0,0 +1,83 @@
+use petgraph::{prelude::*, algo::dijkstra::*, visit::Reversed};
+
+fn char_elevation(c: char) -> i16 {
+    let elevation = match c {
+        'S' => 'a',
+        'E' => 'z',
+        c   => c,
+    };
+
+    ((elevation as u8) - b'a') as i16
+}
+
+fn travelable(dest: char, src: char) -> bool {
+    char_elevation(src) + 1 >= char_elevation(dest)
+}
+
+fn main() {
+    const INPUT: &str = include_str!("../input.txt");
+    
+    let grid = INPUT.lines().collect::<Vec<&str>>();
+    let grid = grid.iter().map(|s| { s.chars().collect::<Vec<char>>() }).collect::<Vec<Vec<char>>>();
+
+    let mut graph: DiGraphMap<(usize, usize), u8> = DiGraphMap::new();
+
+    let height = grid.len();
+    let width = grid[0].len();
+
+    let mut start: (usize, usize) = (0, 0);
+    let mut end: (usize, usize) = (0, 0);
+    let mut starts: Vec<(usize, usize)> = Vec::new();
+
+    for i in 0..height {
+        for j in 0..width {
+            graph.add_node((i, j));
+
+            let c = grid[i][j];
+            if c == 'S' {
+                start = (i, j);
+                starts.push((i, j));
+            } else if c == 'E' {
+                end = (i, j);
+            } else if c == 'a' {
+                starts.push((i, j));
+            }
+        }
+    }
+
+    for i in 0..height {
+        for j in 0..width {
+            let c = grid[i][j];
+
+            let up = i.saturating_sub(1);
+            let down = i + 1;
+            let left = j.saturating_sub(1);
+            let right = j + 1;
+
+            if left != j && travelable(grid[i][left], c) {
+                graph.add_edge((i, j), (i, left), 1);
+            }
+            if right < width && travelable(grid[i][right], c) {
+                graph.add_edge((i, j), (i, right), 1);
+            }
+            if up != i && travelable(grid[up][j], c) {
+                graph.add_edge((i, j), (up, j), 1);
+            }
+            if down < height && travelable(grid[down][j], c) {
+                graph.add_edge((i, j), (down, j), 1);
+            }
+        }
+    }
+
+    let res = dijkstra(&graph, start, Some(end), |_| 1);
+    println!("{} steps from ({}, {})", res[&end], start.0, start.1);
+
+    let res = dijkstra(Reversed(&graph), end, None, |_| 1);
+    let mut min: (i32, usize, usize) = (i32::MAX, 0, 0);
+    for start in starts {
+        if res.contains_key(&start) && res[&start] < min.0 {
+            min = (res[&start], start.0, start.1);
+        }
+    }
+    println!("{} steps from ({}, {})", min.0, min.1, min.2);
+}