Dag 10 aoc, deel 2 was makkelijker dan deel 1

advent_of_code/2024/10/src/main.rs

@@ -0,0 +1,143 @@
+use std::collections::{HashMap, HashSet};
+
+fn parse(input: &str) -> Vec<Vec<u32>> {
+    const RADIX: u32 = 10;
+    input
+        .lines()
+        .map(|l| l.chars().map(|c| c.to_digit(RADIX).unwrap()).collect())
+        .collect()
+}
+
+fn solve_1(input: &str) -> u32 {
+    let map = parse(input);
+
+    let h = map.len();
+    let w = map[0].len();
+
+    let mut map_info: HashMap<(usize, usize), HashSet<(usize, usize)>> = HashMap::new();
+
+    for (j, row) in map.iter().enumerate() {
+        for (i, elevation) in row.iter().enumerate() {
+            if *elevation == 9 {
+                map_info.insert((i, j), HashSet::from([(i, j)]));
+            }
+        }
+    }
+
+    for e in (0..=8).rev() {
+        let mut new_map_info: HashMap<(usize, usize), HashSet<(usize, usize)>> = HashMap::new();
+
+        for ((i, j), trailheads) in map_info.into_iter() {
+            let mut positions = vec![];
+            if i > 0 {
+                positions.push((i - 1, j));
+            }
+            if i < w - 1 {
+                positions.push((i + 1, j));
+            }
+            if j > 0 {
+                positions.push((i, j - 1));
+            }
+            if j < h - 1 {
+                positions.push((i, j + 1));
+            }
+
+            for (x, y) in positions.into_iter() {
+                if map[y][x] == e {
+                    match new_map_info.get(&(x, y)) {
+                        None => new_map_info.insert((x, y), trailheads.clone()),
+                        Some(&ref t) => new_map_info.insert(
+                            (x, y),
+                            t.union(&trailheads).map(|ts| ts.to_owned()).collect(),
+                        ),
+                    };
+                }
+            }
+        }
+        map_info = new_map_info;
+    }
+
+    map_info
+        .values()
+        .map(|trailheads| trailheads.len() as u32)
+        .sum()
+}
+
+fn solve_2(input: &str) -> u32 {
+    let map = parse(input);
+
+    let h = map.len();
+    let w = map[0].len();
+
+    let mut map_info: HashMap<(usize, usize), u32> = HashMap::new();
+
+    for (j, row) in map.iter().enumerate() {
+        for (i, elevation) in row.iter().enumerate() {
+            if *elevation == 9 {
+                map_info.insert((i, j), 1);
+            }
+        }
+    }
+
+    for e in (0..=8).rev() {
+        let mut new_map_info: HashMap<(usize, usize), u32> = HashMap::new();
+
+        for ((i, j), rating) in map_info.into_iter() {
+            let mut positions = vec![];
+            if i > 0 {
+                positions.push((i - 1, j));
+            }
+            if i < w - 1 {
+                positions.push((i + 1, j));
+            }
+            if j > 0 {
+                positions.push((i, j - 1));
+            }
+            if j < h - 1 {
+                positions.push((i, j + 1));
+            }
+
+            for (x, y) in positions.into_iter() {
+                if map[y][x] == e {
+                    match new_map_info.get(&(x, y)) {
+                        None => new_map_info.insert((x, y), rating),
+                        Some(r) => new_map_info.insert((x, y), r + rating),
+                    };
+                }
+            }
+        }
+        map_info = new_map_info;
+    }
+
+    map_info.values().sum()
+}
+
+fn main() {
+    println!("Hello, this is Patrick!");
+
+    let input = include_str!("../input.txt");
+
+    let result_1 = solve_1(input);
+    println!("The sum of scores of all trailheads is {}", result_1);
+
+    let result_2 = solve_2(input);
+    println!("The sum of ratings of all trailheads is {}", result_2);
+}
+
+#[cfg(test)]
+
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1() {
+        let test_input = include_str!("../test.txt");
+        assert_eq!(solve_1(test_input), 36);
+    }
+
+    #[test]
+    fn test_2() {
+        let test_input = include_str!("../test.txt");
+        assert_eq!(solve_2(test_input), 81);
+    }
+}