235. Lowest Common Ancestor of a Binary Search Tree

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST.

According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two
nodes v and w as the lowest node in T that has both v and w as descendants (where we allow a node to be a descendant of itself).”

_______6______
/              \
___2__          ___8__
/      \        /      \
0      _4       7       9
/  \
3   5

For example, the lowest common ancestor (LCA) of nodes 

2

 and 

8

 is 

6

.
Another example is LCA of nodes 

2

 and 

4

 is 

2

,
since a node can be a descendant of itself according to the LCA definition.

public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {

if((root.val>p.val && root.val>q.val)){
return lowestCommonAncestor(root.left, p, q);
}
if((root.val<p.val && root.val<q.val)){
return lowestCommonAncestor(root.right, p, q);
}
return root;

}