def solve(self):
"""Solve the problem
Note: O(n) (runtime) and O(n) (space) solution uses the breadth first traversal to traverse nodes and copy node neighbors.
Args:
Returns:
GraphNode
Raises:
None
"""
print("Solving {} problem ...".format(self.PROBLEM_NAME))
# Create a queue for BFS
nodes_queue = deque()
nodes_queue.append(self.input_graph_node)
# Root node to return for the cloned graph
cloned_graph_node = GraphNode(self.input_graph_node.data)
# Bookkeeping visited nodes -- contains the cloned nodes
visited_dict = {self.input_graph_node: cloned_graph_node}
while len(nodes_queue) > 0:
current_node = nodes_queue.popleft()
copied_node = visited_dict[current_node]
# iterate current node's neighbors
for node in current_node.neighbors:
# if the node is already not visited
if node not in visited_dict:
# append the node to queue
nodes_queue.append(node)
# create a copy node for the neighbor
neighbor_node = GraphNode(node.data)
# add neighbor and update visited
copied_node.add_neighbor(neighbor_node)
visited_dict[node] = neighbor_node
else:
# if the node is already visited
neighbor_node = visited_dict[node]
# Add the neighbor node to the copied node's neighbors if it's not added
if neighbor_node not in copied_node.neighbors:
copied_node.add_neighbor(neighbor_node)
return cloned_graph_node
def test_solve(self):
"""Test solve
Args:
self: TestCloneGraphDepthFirst
Returns:
None
Raises:
None
"""
# Given
'''
Note : All the edges are Undirected
Given Graph:
1--2
| |
4--3
'''
node1 = GraphNode(1)
node2 = GraphNode(2)
node3 = GraphNode(3)
node4 = GraphNode(4)
node1.add_neighbor(node2)
node1.add_neighbor(node4)
node2.add_neighbor(node3)
node2.add_neighbor(node1)
node3.add_neighbor(node4)
node3.add_neighbor(node2)
node4.add_neighbor(node1)
node4.add_neighbor(node3)
clone_graph_problem = CloneGraphDepthFirst(node1)
# When
cloned_graph_node = clone_graph_problem.solve()
# Then
cloned_list = []
Graph.depth_first_traversal(cloned_graph_node, cloned_list)
input_list = []
Graph.depth_first_traversal(node1, input_list)
self.assertEqual(cloned_list, input_list)
def test_solve_invalid(self):
"""Test solve (invalid)
Args:
self: TestIsGraphBipartite
Returns:
None
Raises:
None
"""
# Given
'''
Note : All the edges are Undirected
Given Graph:
1----2
| \ |
| \ |
4----3
'''
node1 = GraphNode(1)
node2 = GraphNode(2)
node3 = GraphNode(3)
node4 = GraphNode(4)
node1.add_neighbor(node2)
node1.add_neighbor(node4)
node1.add_neighbor(node3)
node2.add_neighbor(node3)
node2.add_neighbor(node1)
node3.add_neighbor(node4)
node3.add_neighbor(node2)
node3.add_neighbor(node1)
node4.add_neighbor(node1)
node4.add_neighbor(node3)
is_bipartite_problem = IsGraphBipartite(node1)
# When
result = is_bipartite_problem.solve()
# Then
self.assertFalse(result)
def test_breadth_first_traversal(self):
"""Test for graph node (breadth_first_traversal)
Args:
self: TestGraph
Returns:
None
Raises:
None
"""
# Given
'''
Given Graph:
1--2
| |
4--3
'''
node1 = GraphNode(1)
node2 = GraphNode(2)
node3 = GraphNode(3)
node4 = GraphNode(4)
node1.add_neighbor(node2)
node1.add_neighbor(node4)
node2.add_neighbor(node3)
node2.add_neighbor(node1)
node3.add_neighbor(node4)
node3.add_neighbor(node2)
node4.add_neighbor(node1)
node4.add_neighbor(node3)
# When
result = []
Graph.breadth_first_traversal(node1, result)
# Then
self.assertEqual(result, [1, 2, 4, 3])