From 5c46e12269e6a427a149bd679ff0913d2781aba3 Mon Sep 17 00:00:00 2001
From: Luke Else <mail@luke-else.co.uk>
Date: Mon, 11 Dec 2023 11:30:54 +0000
Subject: [PATCH] Day 10 Part 2 Complete

---
 src/input/day10_test2  | 15 ++++---
 src/solutions/day10.rs | 89 +++++++++++++++++++++++++++++-------------
 2 files changed, 72 insertions(+), 32 deletions(-)

diff --git a/src/input/day10_test2 b/src/input/day10_test2
index 3c00cf2..2e5dcbb 100644
--- a/src/input/day10_test2
+++ b/src/input/day10_test2
@@ -1,5 +1,10 @@
-..F7.
-.FJ|.
-SJ.L7
-|F--J
-LJ...
\ No newline at end of file
+.F----7F7F7F7F-7....
+.|F--7||||||||FJ....
+.||.FJ||||||||L7....
+FJL7L7LJLJ||LJ.L-7..
+L--J.L7...LJS7F-7L7.
+....F-J..F7FJ|L7L7L7
+....L7.F7||L7|.L7L7|
+.....|FJLJ|FJ|F7|.LJ
+....FJL-7.||.||||...
+....L---J.LJ.LJLJ...
\ No newline at end of file
diff --git a/src/solutions/day10.rs b/src/solutions/day10.rs
index f30ffd2..20756b2 100644
--- a/src/solutions/day10.rs
+++ b/src/solutions/day10.rs
@@ -9,37 +9,31 @@ impl Solution for Day10 {
         &self,
         input: &mut Vec<String>,
     ) -> Result<Box<dyn std::fmt::Display + Sync>, Box<dyn std::error::Error>> {
-        let mut start = (0, 0);
-        let mut graph = input
-            .iter()
-            .enumerate()
-            .map(|(r, line)| {
-                line.bytes()
-                    .enumerate()
-                    .map(|(c, tile)| {
-                        if tile == b'S' {
-                            start = (r, c);
-                        }
-                        self.connections(tile)
-                    })
-                    .collect::<Vec<_>>()
-            })
-            .collect::<Vec<_>>();
-        let pipe_loop = "J|-L7F"
-            .bytes()
-            .find_map(|start_tile| {
-                graph[start.0][start.1] = self.connections(start_tile);
-                self.find_loop(&graph, start)
-            })
-            .unwrap();
+        let (start, mut graph) = self.generate_graph(input);
+        let pipe_loop = self.generate_loop(start, &mut graph)?;
         Ok(Box::new(pipe_loop.len() / 2))
     }
 
     fn part2(
         &self,
-        _input: &mut Vec<String>,
+        input: &mut Vec<String>,
     ) -> Result<Box<dyn std::fmt::Display + Sync>, Box<dyn std::error::Error>> {
-        Ok(Box::new("Ready"))
+        let mut ans = 0usize;
+
+        let (start, mut graph) = self.generate_graph(input);
+        let pipe_loop = self.generate_loop(start, &mut graph)?;
+
+        for r in 0..graph.len() {
+            let mut inside = false;
+            for c in 0..graph[0].len() {
+                if !pipe_loop.contains(&(r, c)) {
+                    ans += inside as usize;
+                } else if graph[r][c][0] {
+                    inside = !inside;
+                }
+            }
+        }
+        Ok(Box::new(ans))
     }
 
     fn get_day(&self) -> u8 {
@@ -48,6 +42,8 @@ impl Solution for Day10 {
 }
 
 impl Day10 {
+    /// Traces the graph and populates a hashset with
+    /// loops present within the connections
     fn find_loop(
         &self,
         graph: &[Vec<[bool; 4]>],
@@ -86,6 +82,7 @@ impl Day10 {
         }
     }
 
+    /// Retruns all of the connections around a given tile
     fn connections(&self, tile: u8) -> [bool; 4] {
         match tile {
             //      [   up, right,  down,  left]
@@ -98,6 +95,44 @@ impl Day10 {
             _ => [false, false, false, false],
         }
     }
+
+    /// Fucntion to generate a graph of all of the connections of the the nodes
+    fn generate_graph(&self, input: &mut Vec<String>) -> ((usize, usize), Vec<Vec<[bool; 4]>>) {
+        let mut start = (0, 0);
+        let graph = input
+            .iter()
+            .enumerate()
+            .map(|(r, line)| {
+                line.bytes()
+                    .enumerate()
+                    .map(|(c, tile)| {
+                        if tile == b'S' {
+                            start = (r, c);
+                        }
+                        self.connections(tile)
+                    })
+                    .collect::<Vec<_>>()
+            })
+            .collect::<Vec<_>>();
+
+        (start, graph)
+    }
+
+    /// Function that generates the a hashset of the loops in the graph
+    fn generate_loop(
+        &self,
+        start: (usize, usize),
+        graph: &mut [Vec<[bool; 4]>],
+    ) -> Result<HashSet<(usize, usize)>, Box<dyn std::error::Error>> {
+        let pipe_loop = "J|-L7F"
+            .bytes()
+            .find_map(|start_tile| {
+                graph[start.0][start.1] = self.connections(start_tile);
+                self.find_loop(&graph, start)
+            })
+            .unwrap();
+        Ok(pipe_loop)
+    }
 }
 
 /// Test from puzzle input
@@ -120,7 +155,7 @@ mod test {
             .unwrap()
             .to_string();
 
-        assert_eq!(answer, "Ready");
+        assert_eq!(answer, "8");
     }
 
     #[test]
@@ -137,6 +172,6 @@ mod test {
             .unwrap()
             .to_string();
 
-        assert_eq!(answer, "Ready");
+        assert_eq!(answer, "8");
     }
 }