From a74f02638bc69f5fe16b90d7b63e83243d7ff0c5 Mon Sep 17 00:00:00 2001
From: Philippe Zwietering <philippe.zwietering@gmail.com>
Date: Mon, 9 Jan 2023 03:34:17 +0100
Subject: [PATCH] Finished day 12 aoc with nice iterators

---
 advent_of_code/2022/12/src/main.rs | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/advent_of_code/2022/12/src/main.rs b/advent_of_code/2022/12/src/main.rs
index f5ca6cc..47b10ff 100644
--- a/advent_of_code/2022/12/src/main.rs
+++ b/advent_of_code/2022/12/src/main.rs
@@ -7,6 +7,7 @@ fn main() {
         .collect::<Vec<&str>>();
 
     let mut start = (0, 0);
+    let mut starts = Vec::new();
     let mut end = (0, 0);
     // let mut max_y = 0;
     // let mut max_x = 0;
@@ -25,6 +26,9 @@ fn main() {
                 c = 'z';
                 end = (x, y);
             }
+            if c == 'a' {
+                starts.push((x, y));
+            }
 
             points.insert((x, y), c as i32 - 'a' as i32);
 
@@ -52,6 +56,25 @@ fn main() {
 
     println!("Number of steps taken: {}", r.expect("No path found").1);
 
+    let r = starts.into_iter().map(|s| dijkstra(
+        &s, 
+        |&(x, y)| vec![((x-1, y), points.get(&(x-1, y)), (x, y)), 
+                       ((x+1, y), points.get(&(x+1, y)), (x, y)), 
+                       ((x, y+1), points.get(&(x, y+1)), (x, y)),
+                       ((x, y-1), points.get(&(x, y-1)), (x, y)),]
+            .into_iter()
+            .filter(|&(_, n, c)| match n {
+                None => false,
+                Some(&height) => height <= *points.get(&c).unwrap() + 1,
+            })
+            .map(|(coords, _, _)| (coords, 1)),
+        |&n| n == end))
+        .filter_map(|r| r)
+        .map(|(_, r)| r)
+        .min();
+    
+        println!("Number of steps taken from any a: {}", r.expect("No paths found"));
+
     // Testing the parsing
 
     // for y in 0..=max_y {