841

Author: ProHiryu

DFS/traditionalDFS/841.md

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+## Keys and Rooms
+
+#### Description
+
+[link](https://leetcode.com/problems/keys-and-rooms/)
+
+---
+
+#### Solution
+
+- See Code
+
+---
+
+#### Code
+
+> 最坏情况：O(n^2)
+
+```python
+class Solution:
+    def canVisitAllRooms(self, rooms: List[List[int]]) -> bool:
+        seen = set([0])
+        N = len(rooms)
+        state = [0]
+        while state:
+            r = state.pop()
+            for i in rooms[r]:
+                if i not in seen:
+                    state.append(i)
+                    seen.add(i)
+            if len(seen) == N: return True
+        return False
+```