Add par methods to grid using rayon

Author: prevostc

Cargo.lock

@@ -7,3 +7,6 @@ publish = false
 name = "mygrid"
 test = true
 plugin = false
+
+[dependencies]
+rayon = "1.10.0"

mygrid/Cargo.lock

@@ -7,7 +7,7 @@ use crate::point::Point;
 pub struct Grid<T> {
     pub width: usize,
     pub height: usize,
-    content: Vec<T>,
+    pub(crate) content: Vec<T>,
 }
 
 impl<T> Grid<T> {

mygrid/Cargo.toml

@@ -2,7 +2,9 @@
 // contains everything related to grids, points and directions
 // heavily inspired by the amazing maneatingape repo, from which I learned a lot, plz see:
 // https://github.com/maneatingape/advent-of-code-rust/blob/main/src/util/point.rs
+extern crate rayon;
 
 pub mod direction;
 pub mod grid;
+pub mod par_grid;
 pub mod point;

mygrid/src/grid.rs

@@ -0,0 +1,21 @@
+use rayon::iter::{IntoParallelRefIterator, ParallelIterator};
+use rayon::prelude::*;
+
+use crate::{grid::Grid, point::Point};
+
+impl<T: Sized + Send + Sync + Clone> Grid<T> {
+    pub fn par_iter(&self) -> impl ParallelIterator<Item = &T> {
+        self.content.par_iter()
+    }
+
+    pub fn par_iter_item_and_position<'a>(
+        &'a self,
+    ) -> impl ParallelIterator<Item = (Point, &T)> + 'a {
+        let width = self.width;
+        let height = self.height;
+        self.content
+            .par_iter()
+            .enumerate()
+            .map(move |(i, t)| (Point::new_usize(i / width, i % height), t))
+    }
+}

mygrid/src/lib.rs

@@ -2,15 +2,16 @@ use mygrid::{
     direction::{ALL_AROUND, DOWN, LEFT, RIGHT, UP},
     grid::Grid,
 };
+use rayon::prelude::*;
 
 advent_of_code::solution!(4);
 
 pub fn part_one(input: &str) -> Option<u32> {
     let grid = Grid::new_from_str(input, |c| c);
 
     let res = grid
-        .iter_item_and_position()
-        .flat_map(|(point, &c)| ALL_AROUND.iter().map(move |d| (point, c, *d)))
+        .par_iter_item_and_position()
+        .flat_map_iter(|(point, &c)| ALL_AROUND.iter().map(move |d| (point, c, *d)))
         .filter(|&(_, c, _)| c == 'X')
         .filter(|&(point, _, d)| grid.is_in_bounds(point + (d * 3)))
         .filter(|&(point, _, d)| {