From 69c072e211bdee9b002ace071c49c10f0c3c3f03 Mon Sep 17 00:00:00 2001
From: Wesley Moore <wes@wezm.net>
Date: Sat, 7 Dec 2019 16:16:00 +1100
Subject: [PATCH] Extract out function to build orbit tree

---
 2019/src/bin/day6.rs | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/2019/src/bin/day6.rs b/2019/src/bin/day6.rs
index b1622b2..1e50d25 100644
--- a/2019/src/bin/day6.rs
+++ b/2019/src/bin/day6.rs
@@ -29,6 +29,14 @@ fn parse_input(input: &str) -> Vec<Orbit<'_>> {
 }
 
 fn number_of_orbits(input: &[Orbit<'_>]) -> usize {
+    let nodes = build_tree(input);
+    // Now traverse the node and sum the orbits of each one
+    (0..nodes.len())
+        .map(|index| count_orbits(&nodes, index, 0))
+        .sum()
+}
+
+fn build_tree<'a>(input: &'a [Orbit<'a>]) -> Vec<Node<'a>> {
     // Build the tree from the input
     let mut nodes: Vec<Node<'_>> = Vec::with_capacity(input.len());
 
@@ -65,10 +73,7 @@ fn number_of_orbits(input: &[Orbit<'_>]) -> usize {
             });
     }
 
-    // Now traverse the node and sum the orbits of each one
-    (0..nodes.len())
-        .map(|index| count_orbits(&nodes, index, 0))
-        .sum()
+    nodes
 }
 
 fn count_orbits(nodes: &[Node], node_index: usize, count: usize) -> usize {