lowest-common-ancestor-of-a-binary-search-tree.js

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */

/**
 * @param {TreeNode} root
 * @param {TreeNode} p
 * @param {TreeNode} q
 * @return {TreeNode}
 */
var lowestCommonAncestor = function(root, p, q) {
    if (root.val > p.val && root.val > q.val) {
         return lowestCommonAncestor(root.left, p, q);
     } else if (root.val < p.val && root.val < q.val) {
       return lowestCommonAncestor(root.right, p, q);
   } else {
        return root;
   }
};