Implement 2025 - Day 7 - Part 1

2025/07.rs

@@ -0,0 +1,67 @@
+---cargo
+---
+
+static CONTENT: &'static str = include_str!("./inputs/07_1.txt");
+
+#[derive(Debug, PartialEq)]
+enum Cell {
+    Empty,
+    Split,
+    Sourc,
+    TBeam,
+}
+
+fn main() {
+    let mut grid: Vec<_> = CONTENT.lines().map(|l| l.trim()).filter(|l| !l.is_empty()).map(|l| {
+        l.chars().map(|c| match c {
+            '.' => Cell::Empty,
+            'S' => Cell::Sourc,
+            '^' => Cell::Split,
+            other => unreachable!("Unexpected Input {:?}", other),
+        }).collect::<Vec<_>>()
+    }).collect();
+
+    println!("Grid: {:?}", grid);
+
+    // (x, y)
+    let source = grid.iter().enumerate().flat_map(|(y, row)| core::iter::repeat(y).zip(row.iter().enumerate()).map(|(y, (x, c))| (y, x, c))).find_map(|(y, x, c)| (c == &Cell::Sourc).then_some((x, y))).unwrap();
+    println!("Source {:?}", source);
+
+    let mut splits = 0;
+
+    let mut queue: Vec<(usize, usize)> = vec![(source.0, source.1+1)];
+    while let Some((x, mut y)) = queue.pop() {
+        if grid[y][x] != Cell::Empty {
+            continue;
+        }
+
+        while grid.get(y).map(|r| &r[x]) == Some(&Cell::Empty) {
+            // println!("({}, {})", x, y);
+
+            grid[y][x] = Cell::TBeam;
+            y += 1;
+        }
+
+        match grid.get(y).map(|r| &r[x]) {
+            None => {}
+            Some(Cell::Empty) => unreachable!(),
+            Some(Cell::Sourc) => unreachable!(),
+            Some(Cell::Split) => {
+                // println!("Split");
+                splits += 1;
+
+                if let Some(nx) = x.checked_sub(1) {
+                    queue.push((nx, y));
+                }
+                if x+1 < grid[y].len() {
+                    queue.push((x+1, y));
+                }
+            }
+            Some(Cell::TBeam) => {
+                println!("Beam");
+            }
+        };
+    }
+
+    println!("Splits: {:?}", splits);
+}