Minimize Cameras That Cover a Tree Node and Its Neighbors

### Problem A camera installed on a tree node monitors that node, its parent if present, and its immediate children. Return the fewest cameras needed to cover every node of the given binary tree. Node values do not affect camera coverage. ```cpp class Solution { public: int minCameraCover(TreeNode* root); }; ``` ### Examples **Example 1:** ```text Input: root = [0,0,0] Output: 1 Explanation: One camera at the root covers all three nodes. ``` **Example 2:** ```text Input: root = [0,0,0,0,null,null,0] Output: 2 Explanation: Cameras at the root's two children cover all five nodes. The two outer leaves are four edges apart, so one camera cannot cover both. ``` ### Constraints - The tree contains1 to1000 nodes. - Every node value is0. ### Contract considerations Each camera has radius one edge, not an entire-subtree view. All node values are0 under the source contract. ```hint Read the boundary condition Distinguish a covered root with no camera from a root waiting for its parent to cover it. ``` ### Boundary reminders Each camera has radius one edge, not an entire-subtree view. All node values are0 under the source contract.