图常见算法-广度优先算法python实现

广度优先算法

广度优先搜索：breadth-first search, BFS 该算法用于解决两类问题：
1、节点A到节点B是否有路径？
2、节点A到节点B的哪条路径最短？

算法实现思想：
图的建立使用了散列表，双端队列使用了deque，为了避免死循环，需要使用一个列表searched_queue记录已经查找过的数据

from collections import deque

graph = {}
graph["you"] = ["alice", "bob", "claire"]
graph["bob"] = ["anuj", "peggy"]
graph["alice"] = ["peggy"]
graph["claire"] = ["thom", "jonny"]
graph["anuj"] = []
graph["peggy"] = []
graph["thom"] = ["rico"]
graph["rico"] = []
graph["jonny"] = []

def bsfSearch(name):
search_queue = deque()
search_queue += graph[name]
searched_queue = []
while search_queue:
    person = search_queue.popleft()
    if person not in searched_queue:
        searched_queue.append(person) 
        if person_is_seller(person):
            print("person is : " + person)
            return True
        else:
            search_queue += graph[person]
return False
    
def person_is_seller(name):
return name[-1] == 'o'

bsfSearch("you")