From f2d6ff15e8934ea4677f4e9016501d1b52677667 Mon Sep 17 00:00:00 2001
From: "max.nuding" <max.nuding@uni-konstanz.de>
Date: Mon, 12 Dec 2022 13:47:54 +0100
Subject: [PATCH] dedpulicated coord checking

---
 src/day12/mod.rs | 45 +++++++++++----------------------------------
 1 file changed, 11 insertions(+), 34 deletions(-)

diff --git a/src/day12/mod.rs b/src/day12/mod.rs
index 21b2de6..9d6eebd 100644
--- a/src/day12/mod.rs
+++ b/src/day12/mod.rs
@@ -77,48 +77,25 @@ fn bfs(map: &Vec<Vec<u8>>, start: Coord, target: Coord) -> Option<usize> {
         if next == target {
             return Some(path_length);
         }
-        match make_coord((next.row as isize) + 1, next.col as isize, &map, &visited) {
-            Some(down) if map[next.row][next.col] + 1
-                >= map[down.row][down.col] => {
-                visited[down.row][down.col] = true;
-                queue.push_back((down, path_length + 1));
-            },
-            _ => {}
-        }
-        match make_coord((next.row as isize) - 1, next.col as isize, &map, &visited) {
-            Some(up) if map[next.row][next.col] + 1
-                >= map[up.row][up.col] => {
-                visited[up.row][up.col] = true;
-                queue.push_back((up, path_length + 1));
-            },
-            _ => {}
-        }
-        match make_coord(next.row as isize, (next.col as isize) - 1, &map, &visited) {
-            Some(left) if map[next.row][next.col] + 1
-                >= map[left.row][left.col] => {
-                visited[left.row][left.col] = true;
-                queue.push_back((left, path_length + 1));
-            },
-            _ => {}
-        }
-        match make_coord(next.row as isize, (next.col as isize) + 1, &map, &visited) {
-            Some(right) if map[next.row][next.col] + 1
-                >= map[right.row][right.col] => {
-                visited[right.row][right.col] = true;
-                queue.push_back((right, path_length + 1));
-            },
-            _ => {}
+        for coord in [(1, 0), (-1, 0), (0, 1), (0, -1)]
+            .iter()
+            .filter_map(|(dr, dc)|make_coord((next.row as isize) + dr, (next.col as isize) + dc, &map)) {
+            if map[next.row][next.col] + 1
+                < map[coord.row][coord.col] || visited[coord.row][coord.col] {
+                continue;
+            }
+            visited[coord.row][coord.col] = true;
+            queue.push_back((coord, path_length + 1));
         }
     }
     None
 }
 
-fn make_coord(row: isize, col: isize, map: &Vec<Vec<u8>>, visited: &Vec<Vec<bool>>) -> Option<Coord> {
+fn make_coord(row: isize, col: isize, map: &Vec<Vec<u8>>) -> Option<Coord> {
     if row >= 0
         && col >= 0
         && row < map.len() as isize
-        && (col as usize) < map[row as usize].len()
-        && !visited[row as usize][col as usize] {
+        && (col as usize) < map[row as usize].len() {
         Some(Coord {
             row: row as usize,
             col: col as usize