Rename move functions, remove parameter

src/day09/mod.rs

@@ -1,60 +1,60 @@
 use crate::read;
-use itertools::Itertools;
 use std::collections::HashSet;
 
-#[derive(Debug, PartialEq, Eq, Default, Clone, Copy, Hash)]
+#[derive(Debug, PartialEq, Eq, Default, Clone, Hash)]
 struct Position {
     pub x: i32,
     pub y: i32,
 }
 
 impl Position {
-    pub fn to_right(&self, count: i32) -> Self {
+    pub fn move_right(&self) -> Self {
         Self {
-            x: self.x + count,
+            x: self.x + 1,
             y: self.y,
         }
     }
-    pub fn to_left(&self, count: i32) -> Self {
+    pub fn move_left(&self) -> Self {
         Self {
-            x: self.x - count,
+            x: self.x - 1,
             y: self.y,
         }
     }
-    pub fn to_up(&self, count: i32) -> Self {
+    pub fn move_up(&self) -> Self {
         Self {
             x: self.x,
-            y: self.y - count,
+            y: self.y - 1,
         }
     }
-    pub fn to_down(&self, count: i32) -> Self {
+    pub fn move_down(&self) -> Self {
         Self {
             x: self.x,
-            y: self.y + count,
+            y: self.y + 1,
         }
     }
 
     pub fn follow_head(&self, head: &Position) -> Self {
         if head.x == self.x && head.y > self.y + 1 {
-            self.to_down(1)
+            self.move_down()
         } else if head.x == self.x && head.y < self.y - 1 {
-            self.to_up(1)
+            self.move_up()
         } else if head.x > self.x + 1 && head.y == self.y {
-            self.to_right(1)
+            self.move_right()
         } else if head.x < self.x - 1 && head.y == self.y {
-            self.to_left(1)
+            self.move_left()
         } else if (head.x - self.x).abs() == 1 && (head.y - self.y).abs() == 1 {
-            *self
+            // One away diagonally - don't move
+            self.clone()
         } else if head.x < self.x && head.y < self.y {
-            self.to_left(1).to_up(1)
+            self.move_left().move_up()
         } else if head.x > self.x && head.y < self.y {
-            self.to_right(1).to_up(1)
+            self.move_right().move_up()
         } else if head.x > self.x && head.y > self.y {
-            self.to_right(1).to_down(1)
+            self.move_right().move_down()
         } else if head.x < self.x && head.y > self.y {
-            self.to_left(1).to_down(1)
+            self.move_left().move_down()
         } else {
-            *self
+            self.clone()
         }
     }
 }
@@ -84,17 +84,17 @@ pub fn simulate(num_knots: usize) -> usize {
         let count = count.parse().unwrap();
         for _c in 0..count {
             knots[0] = match dir {
-                "R" => knots[0].to_right(1),
-                "U" => knots[0].to_up(1),
-                "L" => knots[0].to_left(1),
-                "D" => knots[0].to_down(1),
+                "R" => knots[0].move_right(),
+                "U" => knots[0].move_up(),
+                "L" => knots[0].move_left(),
+                "D" => knots[0].move_down(),
                 _ => unreachable!(),
             };
             for i in 1..knots.len() {
                 knots[i] = knots[i].follow_head(&knots[i - 1]);
             }
 
-            visited.insert(*knots.last().unwrap());
+            visited.insert(knots.last().unwrap().clone());
         }
     }
     visited.len()