Update algorithm10.rs

Author: hellolutar

exercises/algorithm/algorithm10.rs

@@ -1,8 +1,7 @@
 /*
-	graph
-	This problem requires you to implement a basic graph functio
+    graph
+    This problem requires you to implement a basic graph functio
 */
-// I AM NOT DONE
 
 use std::collections::{HashMap, HashSet};
 use std::fmt;
@@ -29,16 +28,34 @@ impl Graph for UndirectedGraph {
         &self.adjacency_table
     }
     fn add_edge(&mut self, edge: (&str, &str, i32)) {
-        //TODO
+        let (from, to, weight) = edge;
+
+        self.add_node(from);
+        self.add_node(to);
+
+        self.adjacency_table_mutable()
+            .get_mut(from)
+            .unwrap()
+            .push((to.to_string(), weight));
+
+        self.adjacency_table_mutable()
+            .get_mut(to)
+            .unwrap()
+            .push((from.to_string(), weight));
     }
 }
 pub trait Graph {
     fn new() -> Self;
     fn adjacency_table_mutable(&mut self) -> &mut HashMap<String, Vec<(String, i32)>>;
     fn adjacency_table(&self) -> &HashMap<String, Vec<(String, i32)>>;
     fn add_node(&mut self, node: &str) -> bool {
-        //TODO
-		true
+        let table = self.adjacency_table_mutable();
+        if table.contains_key(node) {
+            false
+        } else {
+            table.insert(node.to_string(), Vec::new());
+            true
+        }
     }
     fn add_edge(&mut self, edge: (&str, &str, i32)) {
         //TODO
@@ -81,4 +98,4 @@ mod test_undirected_graph {
             assert_eq!(graph.edges().contains(edge), true);
         }
     }
-}
+}