Is graph bipartite

Author: ivanmmarkovic

Ch07. Graphs and Graph Algorithms/is-graph-bipartite/graph.py

@@ -0,0 +1,45 @@
+from queue import Queue
+
+class Graph:
+    def __init__(self):
+        self.__vertices__:dict = {}
+        self.__adjacency_map__: dict = {}
+        self.__colors__: dict = {}
+        self.__colors__["red"]: list = []
+        self.__colors__["blue"]: list = []
+
+
+    def add_vertex(self, vertex: str):
+        self.__vertices__[vertex] = vertex
+        self.__adjacency_map__[vertex]:list = []
+
+    def add_edge(self, vertex1: str, vertex2: str):
+        self.__adjacency_map__[vertex1].append(vertex2)
+        self.__adjacency_map__[vertex2].append(vertex1)
+
+    def bipartite_check(self, vertex) -> bool:
+        q: Queue = Queue()
+        for vertex in self.__vertices__:
+            if vertex in self.__colors__["red"] or vertex in self.__colors__["blue"]:
+                continue
+            self.__colors__["red"].append(vertex)
+            q.enqueue(vertex)
+
+            while not q.is_empty():
+                tmp: str = q.dequeue()
+                if tmp in self.__colors__["red"]:
+                    current_color = "red"
+                    opposite_color = "blue"
+                else:
+                    current_color = "blue"
+                    opposite_color = "red"
+                for neighbour in self.__adjacency_map__[tmp]:
+                    if neighbour in self.__colors__[current_color]:
+                        return False
+                    if neighbour not in self.__colors__[opposite_color]:
+                        self.__colors__[opposite_color].append(neighbour)
+                        q.enqueue(neighbour)
+        return True
+
+
+    

Ch07. Graphs and Graph Algorithms/is-graph-bipartite/main.py

@@ -0,0 +1,24 @@
+from graph import Graph
+
+
+g: Graph = Graph()
+g.add_vertex("a")
+g.add_vertex("b")
+g.add_vertex("c")
+g.add_vertex("d")
+
+# a, b ||---|| c, d
+
+
+g.add_edge("a", "c")
+g.add_edge("a", "d")
+
+g.add_edge("b", "c")
+g.add_edge("b", "d")
+
+
+# g.add_edge("a", "b")
+
+print(g.bipartite_check("a"))
+
+

Ch07. Graphs and Graph Algorithms/is-graph-bipartite/queue.py

@@ -0,0 +1,16 @@
+class Queue:
+    def __init__(self):
+        self.__queue__: list = []
+
+    def is_empty(self) -> bool:
+        return len(self.__queue__) == 0
+
+    def enqueue(self, vertex: str):
+        self.__queue__.append(vertex)
+    
+    def dequeue(self):
+        if self.is_empty():
+            raise Exception("Queue is empty")
+        return self.__queue__.pop(0)
+
+