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Merge pull request youngyangyang04#2684 from sunlight0602/105-Complete-Reachability-of-Directed-Graphs

0105.有向图的完全可达性 python BFS solution

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`@@ -290,6 +290,42 @@ int main() {`
`290`	`290`	`### Java`
`291`	`291`
`292`	`292`	`### Python`
	`293`	`+BFS算法`
	`294`	+```Python
	`295`	`+import collections`
	`296`	`+`
	`297`	`+path = set() # 纪录 BFS 所经过之节点`
	`298`	`+`
	`299`	`+def bfs(root, graph):`
	`300`	`+ global path`
	`301`	`+`
	`302`	`+ que = collections.deque([root])`
	`303`	`+ while que:`
	`304`	`+ cur = que.popleft()`
	`305`	`+ path.add(cur)`
	`306`	`+`
	`307`	`+ for nei in graph[cur]:`
	`308`	`+ que.append(nei)`
	`309`	`+ graph[cur] = []`
	`310`	`+ return`
	`311`	`+`
	`312`	`+def main():`
	`313`	`+ N, K = map(int, input().strip().split())`
	`314`	`+ graph = collections.defaultdict(list)`
	`315`	`+ for _ in range(K):`
	`316`	`+ src, dest = map(int, input().strip().split())`
	`317`	`+ graph[src].append(dest)`
	`318`	`+`
	`319`	`+ bfs(1, graph)`
	`320`	`+ if path == {i for i in range(1, N + 1)}:`
	`321`	`+ return 1`
	`322`	`+ return -1`
	`323`	`+`
	`324`	`+`
	`325`	`+if __name__ == "__main__":`
	`326`	`+ print(main())`
	`327`	`+`
	`328`	+```
`293`	`329`
`294`	`330`	`### Go`
`295`	`331`

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