Added queue and graphs to data structures

algorithms/data-structures/graphs/graph.py

@@ -0,0 +1,83 @@
+class Vertex:
+    def __init__(self, node):
+        self.id = node
+        self.adjacent = {}
+
+    def __str__(self):
+        return str(self.id) + ' adjacent: ' + str([x.id for x in self.adjacent])
+
+    def add_neighbor(self, neighbor, weight=0):
+        self.adjacent[neighbor] = weight
+
+    def get_connections(self):
+        return self.adjacent.keys()  
+
+    def get_id(self):
+        return self.id
+
+    def get_weight(self, neighbor):
+        return self.adjacent[neighbor]
+
+class Graph:
+    def __init__(self):
+        self.vert_dict = {}
+        self.num_vertices = 0
+
+    def __iter__(self):
+        return iter(self.vert_dict.values())
+
+    def add_vertex(self, node):
+        self.num_vertices = self.num_vertices + 1
+        new_vertex = Vertex(node)
+        self.vert_dict[node] = new_vertex
+        return new_vertex
+
+    def get_vertex(self, n):
+        if n in self.vert_dict:
+            return self.vert_dict[n]
+        else:
+            return None
+
+    def add_edge(self, frm, to, cost = 0):
+        if frm not in self.vert_dict:
+            self.add_vertex(frm)
+        if to not in self.vert_dict:
+            self.add_vertex(to)
+
+        self.vert_dict[frm].add_neighbor(self.vert_dict[to], cost)
+        self.vert_dict[to].add_neighbor(self.vert_dict[frm], cost)
+
+    def get_vertices(self):
+        return self.vert_dict.keys()
+
+
+# Working of graph is as mentioned:
+# if __name__ == '__main__':
+
+#     g = Graph()
+
+#     g.add_vertex('a')
+#     g.add_vertex('b')
+#     g.add_vertex('c')
+#     g.add_vertex('d')
+#     g.add_vertex('e')
+#     g.add_vertex('f')
+
+#     g.add_edge('a', 'b', 7)  
+#     g.add_edge('a', 'c', 9)
+#     g.add_edge('a', 'f', 14)
+#     g.add_edge('b', 'c', 10)
+#     g.add_edge('b', 'd', 15)
+#     g.add_edge('c', 'd', 11)
+#     g.add_edge('c', 'f', 2)
+#     g.add_edge('d', 'e', 6)
+#     g.add_edge('e', 'f', 9)
+
+#     for v in g:
+#         for w in v.get_connections():
+#             vid = v.get_id()
+#             wid = w.get_id()
+#             print '( %s , %s, %3d)'  % ( vid, wid, v.get_weight(w))
+
+#     for v in g:
+#         print 'g.vert_dict[%s]=%s' %(v.get_id(), g.vert_dict[v.get_id()])

algorithms/data-structures/queues/queues.py

@@ -0,0 +1,39 @@
+# Queue implementation in Python
+
+class Queue:
+
+    def __init__(self):
+        self.queue = []
+
+    # Add an element
+    def enqueue(self, item):
+        self.queue.append(item)
+
+    # Remove an element
+    def dequeue(self):
+        if len(self.queue) < 1:
+            return None
+        return self.queue.pop(0)
+
+    # Display  the queue
+    def display(self):
+        print(self.queue)
+
+    def size(self):
+        return len(self.queue)
+
+# For general working of a queue in python:
+# q = Queue()
+# q.enqueue(1)
+# q.enqueue(2)
+# q.enqueue(3)
+# q.enqueue(4)
+# q.enqueue(5)
+
+# q.display()
+
+# q.dequeue()
+
+# print("After removing an element")
+# q.display()
+