From 67fcde43097fda424fcb66b817ae217de8dd06dc Mon Sep 17 00:00:00 2001
From: hal8174 <henning.lindemann@pm.me>
Date: Sat, 16 Nov 2024 15:46:56 +0100
Subject: [PATCH] Get nodes with max degree first

---
 vertex_cover/src/owned.rs | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/vertex_cover/src/owned.rs b/vertex_cover/src/owned.rs
index 177ae33..d494345 100644
--- a/vertex_cover/src/owned.rs
+++ b/vertex_cover/src/owned.rs
@@ -77,10 +77,11 @@ impl Graph {
         self.vertices[(self.vertices.len() - n)..].iter()
     }
 
-    fn get_vertex_with_degree_greater(&self, min_degree: u16) -> Option<u16> {
+    fn get_vertex_with_max_degree_greater_equal(&self, min_degree: u16) -> Option<u16> {
         self.vertices
             .iter()
-            .find(|&v| v.edges.len() >= min_degree as usize)
+            .max_by_key(|&v| v.edges.len())
+            .filter(|&v| v.edges.len() >= min_degree as usize)
             .map(|v| v.name)
     }
 
@@ -107,12 +108,12 @@ impl Graph {
 }
 
 pub fn binary_vertex(graph: &mut Graph, k: u16) -> Option<Vec<u16>> {
-    let vertex = match graph.get_vertex_with_degree_greater(2) {
+    let vertex = match graph.get_vertex_with_max_degree_greater_equal(2) {
         Some(vertex) => vertex,
         None => {
             return {
                 let mut c = 0;
-                while let Some(vertex) = graph.get_vertex_with_degree_greater(1) {
+                while let Some(vertex) = graph.get_vertex_with_max_degree_greater_equal(1) {
                     graph.remove_vertex(vertex);
                     c += 1;
                 }
@@ -195,7 +196,7 @@ pub fn reduction(graph: &mut Graph, k: u16) -> Option<Vec<u16>> {
         }
 
         r
-    } else if let Some(vertex) = graph.get_vertex_with_degree_greater(2) {
+    } else if let Some(vertex) = graph.get_vertex_with_max_degree_greater_equal(2) {
         graph.remove_vertex(vertex);
 
         match reduction(graph, k - 1) {
@@ -347,7 +348,7 @@ pub fn reduction2(graph: &mut Graph, k: u16) -> Option<Vec<u16>> {
                 }
             }
         }
-    } else if let Some(vertex) = graph.get_vertex_with_degree_greater(3) {
+    } else if let Some(vertex) = graph.get_vertex_with_max_degree_greater_equal(3) {
         if k < 1 {
             return None;
         }