Given the root of a binary tree, return the lowest common ancestor of its deepest leaves. Recall that: The node of a binary tree is a leaf if and only if it has no children The depth of the root of the tree is 0. if the depth of a node is d, the depth of each of its children is d + 1. The lowest common ancestor of a set S of nodes, is the node A with the largest depth such that every node in S is in the subtree with root A. Note: This question is the same as 865: https://leetcode.com/problems/smallest-subtree-with-all-the-deepest-nodes/ Example 1: Input: root = [3,5,1,6,2,0,8,null,null,7,4] Output: [2,7,4] Explanation: We return the node with value 2, colored in yellow in the diagram. The nodes coloured in blue are the deepest leaf-nodes of the tree. Note that nodes 6, 0, and 8 are also leaf nodes, but the depth of them is 2, but the depth of nodes 7 and 4 is 3. Example 2: Input: root = [1] Output: [1] Explanation: The root is the deepest node in the tree, and it's the lca of itself. Example 3: Input: root = [0,1,3,null,2] Output: [2] Explanation: The deepest leaf node in the tree is 2, the lca of one node is itself. Constraints: The number of nodes in the tree will be in the range [1, 1000]. 0 <= Node.val <= 1000 The values of the nodes in the tree are unique.