Package g0901_1000.s0968_binary_tree_cameras

Class Solution

java.lang.Object
g0901_1000.s0968_binary_tree_cameras.Solution
public class Solution extends java.lang.Object
968 - Binary Tree Cameras.

Hard

You are given the root of a binary tree. We install cameras on the tree nodes where each camera at a node can monitor its parent, itself, and its immediate children.

Return the minimum number of cameras needed to monitor all nodes of the tree.

Example 1:

Input: root = [0,0,null,0,0]

Output: 1

Explanation: One camera is enough to monitor all nodes if placed as shown.

Example 2:

Input: root = [0,0,null,0,null,0,null,null,0]

Output: 2

Explanation: At least two cameras are needed to monitor all nodes of the tree. The above image shows one of the valid configurations of camera placement.

Constraints:

  • The number of nodes in the tree is in the range [1, 1000].
  • Node.val == 0

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    minCameraCover(TreeNode root)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • minCameraCover

      public int minCameraCover(TreeNode root)