Lowest Common Ancestor of a Binary Search Tree -- Leetcode

Question:

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.

Answer:
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        if(root==null){
            return null;
        }
       
        if(p.val>q.val){
            TreeNode tmp=q;
            q=p;
            p=tmp;
        }
        //p.val<=q.val
        while(true){
          if(root.val<p.val && root.val<q.val){
            root=root.right;
          }
          else if(root.val>p.val && root.val>q.val){
            root=root.left;
          }
          else{
              break;
          }
        }
        return root;
    }
}