day22 refactored part1 into extra struct

src/tasks/day22.rs

@@ -1,19 +1,40 @@
+use crate::tasks::day22::Equipment::*;
+
 pub fn task1() {
-    let depth: usize = 3879;
-    //let target: (usize, usize) = (8, 713);
-    const TARGET_X: usize = 8;
-    const TARGET_Y: usize = 713;
+    let cave = Cave::create(3879, Node(8, 713, Torch));
 
-    let mut map: Vec<Vec<usize>> = Vec::with_capacity(TARGET_X + 1);
-    let mut inner_vec = Vec::with_capacity(TARGET_Y + 1);
-    inner_vec.resize(TARGET_Y + 1, 0);
-    map.resize(TARGET_X + 1, inner_vec);
+    println!("Sum of erosion indexes: {}", cave.erosion_sum());
+}
 
-    for x in 0..=TARGET_X {
-        for y in 0..=TARGET_Y {
+#[derive(PartialEq)]
+enum Equipment {
+    Torch,
+    Climbing,
+    Neither,
+}
+
+struct Node(usize, usize, Equipment);
+
+struct Cave {
+    map: Vec<Vec<usize>>,
+    target: Node,
+}
+
+impl Cave {
+    fn create(depth: usize, target: Node) -> Self {
+        if target.2 != Torch {
+            panic!("A valid target point needs the torch equipped");
+        }
+        let mut map: Vec<Vec<usize>> = Vec::with_capacity(target.0 + 1);
+        let mut inner_vec = Vec::with_capacity(target.1 + 1);
+        inner_vec.resize(target.1 + 1, 0);
+        map.resize(target.0 + 1, inner_vec);
+
+        for x in 0..=target.0 {
+            for y in 0..=target.1 {
                 let geo_index = match (x, y) {
                     (0, 0) => 0,
-                (TARGET_X, TARGET_Y) => 0,
+                    _ if target.0 == x && target.1 == y => 0,
                     (x, 0) => x * 16807,
                     (0, y) => y * 48271,
                     (x, y) => map[x - 1][y] * map[x][y - 1],
@@ -23,10 +44,20 @@ pub fn task1() {
             }
         }
 
-    // println!("{:?}", map);
-
-    let result: usize = (0..=TARGET_X)
-        .map(|x| (0..=TARGET_Y).map(|y| map[x][y] % 3).sum::<usize>())
-        .sum();
-    println!("Sum of erosion indexes: {}", result);
+        Cave { map, target }
+    }
+
+    fn erosion_sum(&self) -> usize {
+        (0..=self.target.0)
+            .map(|x| {
+                (0..=self.target.1)
+                    .map(|y| self.field_type(x, y))
+                    .sum::<usize>()
+            })
+            .sum()
+    }
+
+    fn field_type(&self, x: usize, y: usize) -> usize {
+        self.map[x][y] % 3
+    }
 }