Dijkstra

Author: ivanmmarkovic

.idea/Problem-Solving-with-Algorithms-and-Data-Structures-using-Python.iml

@@ -5,38 +5,38 @@
 class Graph:
     def __init__(self):
         self._vertices: dict = {}
-        self._prev: dict = {}
         self._adjacency_map: dict = {}
+        self._prev: dict = {}
 
-    def add_vertex(self, label: str = None, weight: int = float("inf")):
-        self._vertices[label] = Vertex(label)
+    def add_vertex(self, label: str):
+        v: Vertex = Vertex(label)
+        self._vertices[label] = v
+        self._adjacency_map[label]: list = []
         self._prev[label] = None
-        self._adjacency_map[label]: dict = {}
 
-    def add_edge(self, label1: str = None, label2: str = None, weight: int = float("inf")):
-        self._adjacency_map[label1][label2] = Vertex(label2, weight)
+    def add_edge(self, label1: str, label2: str, weight: int):
+        self._adjacency_map[label1].append(Vertex(label2, weight))
 
     def dijkstra(self, label: str):
-        self._vertices[label].set_weight(0)
+        self._vertices[label].weight = 0
         pq: PriorityQueue = PriorityQueue()
-        for vertex_label in self._vertices:
-            pq.insert(self._vertices[vertex_label])
+        for label in self._vertices:
+            pq.insert(self._vertices[label])
         while not pq.is_empty():
-            vertex: Vertex = pq.delete_min()
-            for neighbour_label in self._adjacency_map[vertex.get_label()]:
-                neighbour_from_adjacency_map: Vertex = self._adjacency_map[vertex.get_label()][neighbour_label]
-                neighbour_from_vertices: Vertex = self._vertices[neighbour_label]
-                if neighbour_from_vertices.get_weight() > \
-                        vertex.get_weight() + neighbour_from_adjacency_map.get_weight():
-                    neighbour_from_vertices.set_weight(vertex.get_weight() + neighbour_from_adjacency_map.get_weight())
-                    self._prev[neighbour_from_vertices.get_label()] = vertex.get_label()
-                    pq.decrease_key(neighbour_from_vertices.get_key())
-
-    def return_path(self, end_label: str = None) -> str:
-        if self._prev[end_label] is None:
-            return end_label
+            current: Vertex = pq.delete_min()
+            for neighbour in self._adjacency_map[current.label]:
+                v: Vertex = self._vertices[neighbour.label]
+                if current.weight + neighbour.weight < v.weight:
+                    v.weight = current.weight + neighbour.weight
+                    self._prev[v.label] = current.label
+                    pq.decrease_key(v.key)
+
+    def show_path(self, label: str) -> str:
+        if self._prev[label] is None:
+            return label
         else:
-            return self.return_path(self._prev[end_label]) + " -> " + end_label
+            return self.show_path(self._prev[label]) + " -> " + label
+