Added new folder of Evolutionary Algorithms Folder

Graph_Algorithms/src/Dijkstra/Dijkstra.py

@@ -1,68 +1,45 @@
-from collections import defaultdict
-import math
-
-class Graph:
-  def __init__(self):
-    self.nodes = set()
-    self.archs = defaultdict(list)
-    self.values = {}
-
-  def add_node(self, value):
-    self.nodes.add(value)
-
-  def add_edge(self, init_node, final_node, value):
-    self.archs[init_node].append(final_node)
-    self.archs[init_node].append(final_node)
-    self.values[(init_node, final_node)] = value
-
-
-def dijkstra(graph, initial):
-  visited = {initial: 0}
-
-  nodes = set(graph.nodes)
-
-  while nodes:
-    min_node = None
-    for node in nodes:
-      if node in visited:
-        if min_node is None:
-          min_node = node
-        elif visited[node] < visited[min_node]:
-          min_node = node
+"""Dijkstra's algorithm."""
 
-    if min_node is None:
-      break
-
-    nodes.remove(min_node)
-    current_weight = visited[min_node]
-
-    for arch in graph.archs[min_node]:
-      try:
-          weight = current_weight + graph.values[(min_node, arch)]
-      except:
-          weight = current_weight + math.inf
-      if arch not in visited or weight < visited[arch]:
-        visited[arch] = weight
-
-  return visited
-
-
-def main():
-
-    #initializing values
-    g = Graph()
-    g.add_node('a')
-    g.add_node('b')
-    g.add_node('c')
-    g.add_node('d')
-
-    g.add_edge('a', 'b', 10)
-    g.add_edge('b', 'c', 2)
-    g.add_edge('a', 'c', 1)
-    g.add_edge('c', 'd', 1)
-    g.add_edge('b', 'd', 8)
+import math
 
-    #output
-    print(dijkstra(g, 'a'))
 
-main()
+class Vertex:
+
+    def __init__(self, id):
+        self.id = str(id)
+        self.distance = 0
+        self.neighbors = []
+        self.edges = {}  # {vertex:distance}
+
+    def __lt__(self, other):
+        """Comparison rule to < operator."""
+        return self.distance < other.distance
+
+    def __repr__(self):
+        """Return the vertex id."""
+        return self.id
+
+    def add_neighbor(self, vertex):
+        """Add a pointer to a vertex at neighbor's list."""
+        self.neighbors.append(vertex)
+
+    def add_edge(self, vertex, weight):
+        """Destination vertex and weight."""
+        self.edges[vertex.id] = weight
+
+
+def dijkstra(graph, source, destiny):
+    """Dijkstra's Algorithm."""
+    q = []
+    for v in graph:
+        v.distance = math.inf
+        q.append(v)
+    source.distance = 0
+    while q:
+        v = min(q)
+        q.remove(v)
+        for u in v.neighbors:
+            new = v.distance + v.edges[u.id]
+            if new < u.distance:
+                u.distance = new
+    return destiny.distance