Given a binary search tree (BST), find the lowest common ancestor (LCA) node of two given nodes in the BST.
According to the definition of LCA on Wikipedia: "The lowest common ancestor is defined between two nodes p and q as the lowest node in T that has both p and q as descendants (where we allow a node to be a descendant of itself)."
[2, 10⁵].-10⁹ ≤ Node.val ≤ 10⁹Node.val are unique.p and q will exist in the BST.p ≠ qUse the BST property: left child < root < right child.
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