```
class Solution {
public:
TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {
if(!root||!p||!q) return nullptr;
if(root->val < p->val && root->val < q->val)
return lowestCommonAncestor(root->right,p,q);
if(root->val > p->val && root->val > q->val)
return lowestCommonAncestor(root->left,p,q);
else
return root;
}
};
```