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

0105.有向图的完全可达性 python BFS solution

Author: youngyangyang04

problems/kamacoder/0105.有向图的完全可达性.md

@@ -290,6 +290,42 @@ int main() {
 ### Java 
 
 ### Python
+BFS算法
+```Python
+import collections
+
+path = set()  # 纪录 BFS 所经过之节点
+
+def bfs(root, graph):
+    global path
+    
+    que = collections.deque([root])
+    while que:
+        cur = que.popleft()
+        path.add(cur)
+        
+        for nei in graph[cur]:
+            que.append(nei)
+        graph[cur] = []
+    return
+
+def main():
+    N, K = map(int, input().strip().split())
+    graph = collections.defaultdict(list)
+    for _ in range(K):
+        src, dest = map(int, input().strip().split())
+        graph[src].append(dest)
+    
+    bfs(1, graph)
+    if path == {i for i in range(1, N + 1)}:
+        return 1
+    return -1
+        
+
+if __name__ == "__main__":
+    print(main())
+
+```
 
 ### Go