1123. Lowest Common Ancestor of Deepest Leaves

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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`

.

**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**.

**Note:** This question is the same as 865: https://leetcode.com/problems/smallest-subtree-with-all-the-deepest-nodes/

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