Package g0901_1000.s0968_binary_tree_cameras

Class Solution

java.lang.Object

g0901_1000.s0968_binary_tree_cameras.Solution

public class Solution
extends Object

968 - Binary Tree Cameras.<p>Hard</p> <p>You are given the <code>root</code> 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.</p> <p>Return <em>the minimum number of cameras needed to monitor all nodes of the tree</em>.</p> <p><strong>Example 1:</strong></p> <p><img src="https://assets.leetcode.com/uploads/2018/12/29/bst_cameras_01.png" alt="" /></p> <p><strong>Input:</strong> root = [0,0,null,0,0]</p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong> One camera is enough to monitor all nodes if placed as shown.</p> <p><strong>Example 2:</strong></p> <p><img src="https://assets.leetcode.com/uploads/2018/12/29/bst_cameras_02.png" alt="" /></p> <p><strong>Input:</strong> root = [0,0,null,0,null,0,null,null,0]</p> <p><strong>Output:</strong> 2</p> <p><strong>Explanation:</strong> 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.</p> <p><strong>Constraints:</strong></p> <ul> <li>The number of nodes in the tree is in the range <code>[1, 1000]</code>.</li> <li><code>Node.val == 0</code></li> </ul>

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)