Lowest Common Ancestor of Binary Search Tree (BST)

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

Thoughts:

1. 两个节点在同一个子树（左子树，右子树）， recursive搜索

2. 不在同一个子树，当下的根节点就是他们的共同节点

Solution:

Node* findLCA(Node *tree, Node *n1, Node *n2)
{
if(!tree || !n1 || !na) return NULL;
else if (max(n1->val, n2->val) > tree->val)
findLCA(tree->right, n1, n2);
else if(min(n1->val, n2->val) < tree->val)
findLCA(tree->left, n1, n2);
else return tree;
}