solved day 6 part 2

day06/src/main.rs

@@ -16,7 +16,9 @@ enum Switch {
 }
 
 #[derive(Debug)]
-enum ParseLineError {}
+enum ParseLineError {
+    WrongKeyword,
+}
 
 impl std::fmt::Display for ParseLineError {
     fn fmt(&self, _: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -60,7 +62,7 @@ impl FromStr for Switch {
             "turn on" => Switch::On(rect),
             "turn off" => Switch::Off(rect),
             "toggle" => Switch::Toggle(rect),
-            _ => unreachable!(),
+            _ => return Err(ParseLineError::WrongKeyword),
         };
 
         Ok(instance)
@@ -75,6 +77,8 @@ fn main() {
         .collect();
 
     part_1(&data);
+
+    part_2(&data);
 }
 
 #[allow(clippy::needless_range_loop)]
@@ -119,3 +123,44 @@ fn part_1(data: &[Switch]) {
 
     println!("{sum}");
 }
+
+#[allow(clippy::needless_range_loop)]
+fn part_2(data: &[Switch]) {
+    let mut grid = vec![vec![0_usize; 1000]; 1000];
+
+    for task in data {
+        match task {
+            Switch::On(rect) => {
+                for x in rect.0.0..=rect.1.0 {
+                    for y in rect.0.1..=rect.1.1 {
+                        grid[x][y] += 1;
+                    }
+                }
+            }
+            Switch::Off(rect) => {
+                for x in rect.0.0..=rect.1.0 {
+                    for y in rect.0.1..=rect.1.1 {
+                        grid[x][y] = grid[x][y].saturating_sub(1);
+                    }
+                }
+            }
+            Switch::Toggle(rect) => {
+                for x in rect.0.0..=rect.1.0 {
+                    for y in rect.0.1..=rect.1.1 {
+                        grid[x][y] += 2;
+                    }
+                }
+            }
+        }
+    }
+
+    let mut sum = 0;
+
+    for x in 0..1000 {
+        for y in 0..1000 {
+            sum += grid[x][y];
+        }
+    }
+
+    println!("{sum}");
+}