Main68.java

package JZOffer2;

public class Main68 {
    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        while(root!=null){
            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;
    }

    public TreeNode lowestCommonAncestor1(TreeNode root, TreeNode p, TreeNode q) {
        if(root.val < p.val && root.val < q.val)
            return lowestCommonAncestor1(root.right, p, q);
        if(root.val > p.val && root.val > q.val)
            return lowestCommonAncestor1(root.left, p, q);
        return root;
    }
}