def queue_operations():
'''USER OPERATIONS OF A QUEUE IMPLEMENTATION'''
queue = Queue()
while choice > 0:
queue_menu = [('MAIN MENU', -1), ('EXIT', 0), \
('ENQUEUE', 1), ('DEQUEUE', 2), ('FRONT', 3), ('REAR', 4), ('SIZE', 5)]
print_menu(queue_menu)
choice = int(input().strip())
if choice == 1:
print('ENTER ITEM :', end=' ')
queue.enqueue(int(input().strip()))
print('ENQUEUE OPERATION SUCCESSFUL.')
elif choice == 2:
if queue.is_empty():
print('UNDERFLOW')
else:
print('DEQUEUED VALUE :', queue.dequeue())
elif choice == 3:
if queue.is_empty():
print('UNDERFLOW')
else:
print('FRONT :', queue.front())
elif choice == 4:
if queue.is_empty():
print('UNDERFLOW')
else:
print('REAR :', queue.rear())
elif choice == 5:
print('QUEUE SIZE :', queue.size())
def bfs_paths(graph, source, destination):
'''ALL POSSIBLE PATHS FROM SOURCE TO DESTINATION USING BREADTH-FIRST SEARCH'''
queue = Queue()
queue.enqueue((source, [source]))
while not queue.is_empty():
(vertex, path) = queue.dequeue()
for next_node in graph[vertex].keys():
if next_node == destination:
yield path + [next_node]
else:
queue.enqueue((next_node, path + next_node))
def bfs(graph, source):
'''BREADTH-FIRST SEARCH'''
queue = Queue()
visited, distance = set(), {}
distance[source] = 0
queue.enqueue(source)
visited.add(source)
while not queue.is_empty():
u = queue.dequeue()
for v in graph[u].keys():
if v not in visited:
visited.add(v)
distance[v] = distance[u] + 1
queue.enqueue(v)
return distance
