grid: add add_mut()

README.md

@@ -1,6 +1,6 @@
 <!-- AOC TILES BEGIN -->
 <h1 align="center">
-  2024 - 31 ⭐ - Rust
+  2024 - 32 ⭐ - Rust
 </h1>
 <a href="src/day1.rs">
   <img src=".aoc_tiles/tiles/2024/01.png" width="161px">

utils/grid/lib.rs

@@ -181,6 +181,12 @@ impl<T: Clone + Eq + PartialEq + Debug> Grid<T> {
             None => None,
         }
     }
+    pub fn get_mut<C: AsCoord2d>(&mut self, c: &C) -> Option<&mut T> {
+        match self.valid_pos(c) {
+            Some(pos) => Some(self.data.get_mut(pos).unwrap()),
+            None => None,
+        }
+    }
     pub fn set<C: AsCoord2d>(&mut self, c: &C, mut val: T) -> Option<T> {
         match self.valid_pos(c) {
             Some(pos) => {