day 14 part 1

example.txt

@@ -1,15 +1,10 @@
-#.##..##.
-..#.##.#.
-##......#
-##......#
-..#.##.#.
-..##..##.
-#.#.##.#.
-
-#...##..#
-#....#..#
-..##..###
-#####.##.
-#####.##.
-..##..###
-#....#..#
+O....#....
+O.OO#....#
+.....##...
+OO.#O....O
+.O.....O#.
+O.#..O.#.#
+..O..#O..O
+.......O..
+#....###..
+#OO..#....

src/main.rs

@@ -1,72 +1,35 @@
 use anyhow::Result;
-use std::{collections::HashSet, io::stdin, vec};
+use std::io::stdin;
 
 type Grid = Vec<Vec<char>>;
 
-fn vertical_mirror_points(grid: &Grid) -> HashSet<usize> {
-    let mut s = HashSet::new();
-    for x in 1..grid[0].len() {
-        let mut differences = 0;
-        for row in grid {
-            for i in 0..x {
-                if x + i >= row.len() {
-                    continue;
-                }
-                if row[x - i - 1] != row[x + i] {
-                    differences += 1;
-                }
-            }
-        }
-        if differences == 1 {
-            s.insert(x);
-        }
-    }
-    s
-}
-
-fn horizontal_mirror_points(grid: &Grid) -> HashSet<usize> {
-    let mut s = HashSet::new();
-    for y in 1..grid.len() {
-        let mut differences = 0;
-        for x in 0..grid[0].len() {
-            for i in 0..y {
-                if y + i >= grid.len() {
-                    continue;
-                }
-                if grid[y - i - 1][x] != grid[y + i][x] {
-                    differences += 1;
-                }
-            }
-        }
-        if differences == 1 {
-            s.insert(y);
-        }
-    }
-    s
-}
-
 fn main() -> Result<()> {
-    let mut grids: Vec<Grid> = vec![];
-    grids.push(vec![]);
+    let mut grid: Grid = vec![];
     for line in stdin().lines().map_while(Result::ok) {
-        if line.is_empty() {
-            grids.push(vec![]);
-            continue;
+        grid.push(line.chars().collect());
     }
-        grids.last_mut().unwrap().push(line.chars().collect());
+
+    let height = grid.len();
+    let width = grid[0].len();
+    let mut total_load = 0;
+    for x in 0..width {
+        let mut column_load = 0;
+        let mut load = height;
+        for (y, row) in grid.iter().enumerate() {
+            match row[x] {
+                'O' => {
+                    column_load += load;
+                    load -= 1;
                 }
-    let mut sum = 0;
-    for (i, grid) in grids.iter().enumerate() {
-        for v in vertical_mirror_points(grid) {
-            println!("grid {i}: v = {v}");
-            sum += v;
+                '#' => {
+                    load = height - y - 1;
                 }
-        for h in horizontal_mirror_points(grid) {
-            println!("grid {i}: h = {h}");
-            sum += 100 * h;
+                _ => {}
             }
         }
-    println!("{sum}");
+        total_load += column_load;
+    }
+    println!("{total_load}");
     Ok(())
 }