经典算法python代码实现

广度优先搜索、深度优先搜索

class graph():
def __init__(self,*arg,**kwargs):
self.node_neighbors={}
self.visited={}

def add_nodes(self,nodelist):
for node in nodelist:
self.add_node(node)

def add_node(self,node):
if node not in self.node_neighbors.keys:
self.node_neighbors[node]=[]

def add_edge(self,edge):
u,v=edge
if (u not in self.node_neighbors[v]) and (v not in self.node_neighbors[u]):
self.node_neighbors[u].append(v)
if u!=v:
self.node_neighbors[v].append(u)

def depth_first_search(self,root=None):
self.visited={}
order=[]
def dfs(n):
self.visited
=True
order.append(n)
for node in self.node_neighbors
:
if node not in self.visited:
dps(node)
if root:
dps(root)
for n in self.node_neighbors.keys:
if n not in self.visited:
dps(n)
print(order)
return order

def breadth_first_search(self,root=None):
self.visited={}
order=[]
queue=[]
def bfs():
while(len(queue)>0):
node = queue.pop(0)
self.visited[node]=True
for n in self.node_neighbors[node]:
if not n in self.visited and not n in queue:
order.append(n)
queue.append(n)

if root:
queue.append(root)
order.append(root)
bfs()

for node in self.nodes():
if not node in self.visited:
queue.append(node)
order.append(node)
bfs()
print (order)

return order

if __name__ == '__main__':
g = Graph()
g.add_nodes([i+1 for i in range(8)])
g.add_edge((1, 2))
g.add_edge((1, 3))
g.add_edge((2, 4))
g.add_edge((2, 5))
g.add_edge((4, 8))
g.add_edge((5, 8))
g.add_edge((3, 6))
g.add_edge((3, 7))
g.add_edge((6, 7))
print ("nodes:", g.node_neighbors)

order = g.breadth_first_search(1)
order = g.depth_first_search(1)