Fix: Was broken in a number of creative ways, now tested to be functional

src/main.rs

@@ -1,4 +1,4 @@
-use std::collections::HashMap;
+use std::{collections::HashMap, hash::Hash};
 
 fn main() {
     let mut pages: Graph<char> = Graph::new();
@@ -8,69 +8,82 @@ fn main() {
     pages.add_page('D');
     pages.add_page('E');
 
-    println!("{pages:?}");
+    pages.add_link('A', 'E');
-    pages.link_page('B', 'A');
-    pages.link_page('C', 'B');
-    pages.link_page('D', 'C');
-    pages.link_page('B', 'D');
-    pages.link_page('E', 'D');
-    pages.link_page('A', 'E');
-    pages.link_page('B', 'E');
-    println!("{pages:?}");
 
-    println!("{:?} -> B", pages.get_links('B'));
+    pages.add_link('B', 'A');
-    let p = pages.clone();
+    pages.add_link('B', 'D');
-    for page in p.items {
+    pages.add_link('B', 'E');
-        println!("PageRank {page} => {}", pages.page_rank(page, 10))
+
+    pages.add_link('C', 'B');
+
+    pages.add_link('D', 'C');
+
+    pages.add_link('E', 'D');
+    
+    // println!("{pages:?}");
+    pages.page_rank(40);
+    for (page, score) in pages.get_sorted_scores() {
+        println!("{page} => {score:.2}")
     }
 }
 
 #[derive(Debug, Clone)]
 pub struct Graph<T> {
-    items: Vec<T>,
+    nodes: HashMap<T, Node<T>>,
-    links: HashMap<usize, Vec<usize>>,
+    damping: f64,
-    pub damping_factor: f64
 }
 
-impl<T: Ord + Copy> Graph<T> {
+#[derive(Debug, Clone)]
+pub struct Node<T> {
+    incoming_links: Vec<T>,
+    outgoing_links: Vec<T>,
+    score: f64,
+}
+
+impl<T> Node<T> {
     pub fn new() -> Self {
-        Graph { items: vec![], links: HashMap::new(), damping_factor: 0.85 }
+        Node { incoming_links: vec![], outgoing_links: vec![], score: 1.0 }
+    }
+}
+
+impl<T: Hash + Eq + PartialEq + Clone> Graph<T> {
+    pub fn new() -> Self {
+        Graph { nodes: HashMap::new(), damping: 0.85 }
     }
 
-    pub fn add_page(&mut self, item: T) {
+    pub fn add_page(&mut self, value: T) {
-        self.items.push(item);
+        self.nodes.insert(value, Node::new());
-        self.items.sort();
-        let index = self.find_item(item); 
-        self.links.insert(index, vec![]);
-    }
-    
-    pub fn link_page(&mut self, item: T, link: T) {
-        let item = self.find_item(item);
-        let link = self.find_item(link);
-        self.add_link(item, link)
     }
 
-    fn add_link(&mut self, item_index: usize, link_index: usize) {
+    pub fn add_link(&mut self, link: T, page: T) {
-        self.links.get_mut(&item_index).unwrap().push(link_index);
+        self.nodes.get_mut(&link).unwrap().incoming_links.push(page.clone());
+        self.nodes.get_mut(&page).unwrap().outgoing_links.push(link);
     }
 
-    fn find_item(&self, item: T) -> usize {
+    pub fn page_rank(&mut self, depth: usize) {
-        self.items.binary_search(&item).unwrap()
+        if depth == 0 { return }
+
+        let nodes = self.nodes.clone();
+        for (_, node) in self.nodes.iter_mut() {
+            let mut link_scores = 0.0;
+            for link in node.incoming_links.iter() {
+                let n = nodes.get(link).unwrap();
+                link_scores += n.score / n.outgoing_links.len() as f64
+            }
+            node.score = (1.0 - self.damping) + (self.damping * link_scores)
+        }
+
+        self.page_rank(depth - 1)
     }
 
-    pub fn get_links(&self, item: T) -> Vec<T> {
+    pub fn get_sorted_scores(&self) -> Vec<(T, f64)> {
-        let item = self.find_item(item);
+        let mut scores = vec![];
-        self.links.get(&item).unwrap()
+        for (key, node) in &self.nodes {
-            .to_vec().iter().map(|i| self.items[*i]).collect()
+            scores.push((key.clone(), node.score))
-    }
+        }
+        scores.sort_by(|a, b| 
+            a.1.partial_cmp(&b.1).unwrap());
 
-    pub fn page_rank(&self, item: T, depth: i32) -> f64 {
+        scores
-        if depth == 0 { return 0.0; }
-
-        let links = self.get_links(item);
-        let link_sums: f64 = links.clone().iter().map(
-            |i| self.page_rank(*i, depth - 1) / self.get_links(*i).len() as f64
-        ).sum();
-        return (1.0 - self.damping_factor) + self.damping_factor * link_sums
     }
 }