最低公共祖先节点

给定二叉树的两个节点node1和node2，找到他们的最低公共祖先节点

#include 
using namespace std;
class Node{
public:
    int data;
    Node* left;
    Node* right;
    Node(int val){
        data = val;
        left = right = NULL;
    }
};

Node* lca(Node* head, Node* node1, Node* node2){
    if(head == NULL || head == node1 || head == node2){
        return head;
    }
    
    Node* left = lca(head->left, node1, node2);
    Node* right = lca(head->right, node1, node2);
    if(left!=NULL && right!=NULL){
        return head;
    }
    return left!=NULL ? left : right;
}