Binary Tree Cameras
You are given the root of a binary tree. You may install cameras on nodes, where each camera monitors:
- The node on which it is installed.
- Its parent.
- Its immediate left and right children.
Your task is to determine the minimum number of cameras required so that every node in the binary tree is monitored.
Return the minimum number of cameras needed.
Input: root = [0,0,null,0,0]
Output: 1
Explanation: A single camera placed on the second node can monitor all nodes in the tree.
Input: root = [0,0,null,0,null,0,null,null,0]
Output: 2
Explanation: At least two cameras are required to monitor every node in this skewed tree.
Input: root = [0]
Output: 1
Explanation: A single node needs one camera to be monitored.
- 1 = Number of nodes = 1000
- -10? = Node.data = 10?
See how the best solutions work
Approach, complexity and clean code in every language. Sign in to unlock the editorial.
Keep every attempt
Your submissions, results and runtime history live here. Sign in to start your streak.
1 2 3 4 5 6 7
2
10 5 15 2 7 12 20
2