def dijkstra(aGraph: Graph, start: Vertex):
pq = PriorityQueue()
start.setDistance(0)
pq.buildHeap([(v.getDistance(), v) for v in aGraph])
while not pq.isEmpty():
currentVert = pq.delMin()
for nextVert in currentVert.getConnections():
newDist = currentVert.getDistance() + currentVert.getWeight(
nextVert)
if newDist < nextVert.getDistance():
nextVert.setDistance(newDist)
nextVert.setPred(currentVert)
pq.decreaseKey(nextVert, newDist)
def dfsvisit(self, startVertex: Vertex):
startVertex.setColor("gray")
self.time += 1
startVertex.setDiscovery(self.time)
for nextVertex in startVertex.getConnections():
if nextVertex.getColor() == "white":
nextVertex.setPred(startVertex)
self.dfsvisit(nextVertex)
startVertex.setColor("black")
self.time += 1
startVertex.setFinish(self.time)
def prim(G: Graph, start: Vertex):
pq = PriorityQueue()
for v in G:
v.setDistance(sys.maxsize)
v.setPred(None)
start.setDistance(0)
pq.buildHeap([(v.getDistance(), v) for v in G])
while not pq.isEmpty():
currentVert = pq.delMin()
for nextVert in currentVert.getConnections():
newCost = currentVert.getWeight(nextVert)
if nextVert in pq and newCost < nextVert.getDistance():
nextVert.setPred(currentVert)
nextVert.setDistance(newCost + currentVert.getDistance())
pq.decreaseKey(nextVert, newCost)
def bfs(g: Graph, start: Vertex):
start.setDistance(0)
start.setPred(None)
vertQueue = Queue()
vertQueue.enqueue(start)
while vertQueue.size() > 0:
currentVert = vertQueue.dequeue()
for nbr in currentVert.getConnections():
if nbr.getColor() == 'white':
nbr.setColor('gray')
nbr.setDistance(currentVert.getDistance() + 1)
nbr.setPred(currentVert)
vertQueue.enqueue(nbr)
currentVert.setColor('black')
def dfsVisit(self, startVertex: Vertex):
startVertex.setColor('gray')
self.time += 1
startVertex.setDiscovery(self.time)
for nextVertex in startVertex.getConnections():
if nextVertex.getColor() == 'white':
nextVertex.setPred(startVertex)
self.dfsVisit(nextVertex)
startVertex.setColor('black')
self.time += 1
startVertex.setFinish(self.time)
def knightTour(n, path, u: Vertex, limit):
u.setColor("gray")
path.append(u)
if n < limit:
nbrList = list(u.getConnections())
# nbrList = orderByAvail(u)
i = 0
done = False
while i < len(nbrList) and not done:
if nbrList[i].getColor() == "white":
done = knightTour(n + 1, path, nbrList[i], limit)
i = i + 1
if not done:
path.pop()
u.setColor("white")
else:
done = True
return done
def main():
start = bankCounts(
3, 3, 1
) #The list contains the left bank counts for missionaries, cannibals, and the boat in that order
goal = bankCounts(0, 0, 0)
validTest = start.is_valid(3, 3, 1)
print(validTest)
vertex = Vertex(start)
graph = buildGraph(counts)
print(graph.getVertices)
breadthFirstSearch = bfs(graph, vertex)
def orderByAvail(n: Vertex):
resList = []
for v in n.getConnections():
if v.getColor() == "white":
c = 0
for w in v.getConnections():
if w.getColor() == "white":
c = c + 1
resList.append((c, v))
resList.sort(key=lambda x: x[0])
return [y[1] for y in resList]
def knightTour(n, path, u: Vertex, limit):
u.setColor('gray')
path.append(u)
if n < limit:
nbrList = list(u.getConnections())
i = 0
done = False
while i < len(nbrList) and not done:
if nbrList[i].getColor() == 'white':
done = knightTour(n + 1, path, nbrList[i], limit)
i += 1
if not done: # prepare to backtrack
path.pop()
u.setColor('white')
else:
done = True
return done
def dfs(vertex: Vertex, i):
vertex.color = 'gray'
path.append(str(vertex.id))
if i >= n:
return True
find = False
for neighbor in get_neighbors(vertex, strategy=order_by_avail):
if neighbor.color != 'white':
continue
find = dfs(neighbor, i + 1)
if find:
break
path.pop()
neighbor.color = 'white'
return find
def main(args):
# TODO: add proper TESTs to initialize Graph and Vertex with graph example from GeeksForGeeks!
# print type(Graph)
# print dir(Graph)
# print type(Vertex)
# print dir(Vertex)
# help(Vertex.__init__)
# print dir(PriorityQueue)
vertex0 = Vertex(0)
vertex0.setDistance(0)
# print vertex0
vertex1 = Vertex(1)
# print vertex1
vertex7 = Vertex(7)
# print vertex7
vertex2 = Vertex(2)
# print vertex2
graph1 = Graph()
graph1.addVertex(vertex0)
graph1.addVertex(vertex1)
graph1.addVertex(vertex7)
graph1.addVertex(vertex2)
print 'Initialized Vertex Dump:'
# for aVertex in graph1.getVertices():
# print aVertex
print 'Initialized Edges Dump:'
graph1.addEdge(vertex0, vertex1, 4)
graph1.addEdge(vertex0, vertex7, 8)
graph1.addEdge(vertex1, vertex2, 8)
print 'Vertex Sequenced after Djikstra from starting point with key 0'
try:
dijkstra(graph1, vertex0)
for aVertex in graph1.getVertices():
print aVertex
except Exception as ex:
logging.exception("BURP!")
def add_vertex(self, key):
self.vertexes[key] = Vertex(key)
currentVert = vertQueue.dequeue()
# 遍历多有的边
for nbr in currentVert.getConnections():
if (nbr.getColor() == 'white'):
nbr.setColor('gray')
nbr.setDistance(currentVert.getDistance() + 1)
nbr.setPred(currentVert)
vertQueue.enqueue(nbr)
currentVert.setColor('black')
wordFile = './DS7_Graph/word.txt'
g = buildGraph(wordFile).getVertices()
start = Vertex('FOOL')
print(bsf(g, start))
def traverse(e):
x = e
while (x.getPred()):
print(x.getId())
x.getPred()
print(x.getId())
'''
s:'FOOL'
相邻点：pool，foil，foul，cool
def bfs(g, start):
# 设置距离为0，前导为None
start.setDistance(0)
start.setPred(None)
vertQueue = Queue()
vertQueue.enqueue(start)
while (vertQueue.size() > 0):
currentVert = vertQueue.dequeue()
for nbr in currentVert.getConnections():
if (nbr.getColor() == 'white'):
nbr.setColor('gray')
nbr.setDistance(currentVert.getDistance() + 1)
nbr.setPred(currentVert)
vertQueue.enqueue(nbr)
currentVert.setColor('black')
start = Vertex(0)
print(bfs(g, start))
def traverse(y):
x = y
while (x.getPred()):
print(x.getId())
x = x.getPred()
print(x.getId())
# print(g.getVertex('FOOL'))
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 addVertex(self,key):
self.numVertices = self.numVertices + 1
newVertex = Vertex(key)
self.vertList[key] = newVertex
return newVertex
def addVertex(self, key):
#increments the vertices counter, instaniates a new vertex object, adds that new vertex object to graph dictionary.
self.numVertices = self.numVertices + 1
newVertex = Vertex(key)
self.vertList[key] = newVertex
return newVertex