1 files changed, 68 insertions, 0 deletions
diff --git a/src/bin/2021/day15.rs b/src/bin/2021/day15.rs
new file mode 100644
index 0000000..ca7a72f
--- /dev/null
+++ b/src/bin/2021/day15.rs
@@ -0,0 +1,68 @@
+use advent_of_code::prelude::*;
+
+pub struct Map {
+    grid: Grid<u8>,
+}
+
+impl advent_of_code::graph::Graph<(Row, Col), (Row, Col)> for Map {
+    type Edges = advent_of_code::grid::Adjacent;
+
+    fn edges(&self, v: (Row, Col)) -> Self::Edges {
+        self.grid.adjacent(v.0, v.1, false)
+    }
+
+    fn edge(&self, _v: (Row, Col), e: (Row, Col)) -> ((Row, Col), u64) {
+        (e, u64::from(self.grid[e.0][e.1]))
+    }
+}
+
+pub fn parse(fh: File) -> Result<Map> {
+    Ok(Map {
+        grid: parse::digit_grid(parse::raw_lines(fh)),
+    })
+}
+
+pub fn part1(map: Map) -> Result<u64> {
+    Ok(map
+        .dijkstra(
+            (Row(0), Col(0)),
+            (map.grid.rows() - 1, map.grid.cols() - 1),
+        )
+        .0)
+}
+
+pub fn part2(map: Map) -> Result<u64> {
+    let mut large_grid = Grid::default();
+    large_grid.grow(Row(map.grid.rows().0 * 5), Col(map.grid.cols().0 * 5));
+    for lrow in 0..5 {
+        for lcol in 0..5 {
+            for ((Row(row), Col(col)), val) in map.grid.indexed_cells() {
+                let mut val = val + lrow + lcol;
+                while val > 9 {
+                    val -= 9;
+                }
+                large_grid[Row(usize::from(lrow) * map.grid.rows().0 + row)]
+                    [Col(usize::from(lcol) * map.grid.cols().0 + col)] = val;
+            }
+        }
+    }
+    let large_map = Map { grid: large_grid };
+    Ok(large_map
+        .dijkstra(
+            (Row(0), Col(0)),
+            (large_map.grid.rows() - 1, large_map.grid.cols() - 1),
+        )
+        .0)
+}
+
+#[test]
+fn test() {
+    assert_eq!(
+        part1(parse(parse::data(2021, 15).unwrap()).unwrap()).unwrap(),
+        441
+    );
+    assert_eq!(
+        part2(parse(parse::data(2021, 15).unwrap()).unwrap()).unwrap(),
+        2849
+    );
+}