/**
knakul853
 */

class Solution {
public:
    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {

        if( !root) return NULL;

        int val = root->val;

        if(val > p->val && val > q->val)
            return lowestCommonAncestor(root->left, p,q);

        if(val < p->val && val< q->val)
            return lowestCommonAncestor(root->right, p,q);

        return root;


    }
};