class Solution {
public:
    TreeNode* ans;

    bool dfs(TreeNode* root, TreeNode* p, TreeNode* q)
    {
        if(root == nullptr)
        {
            return false;
        }

        bool lson = dfs(root->left, p, q);
        bool rson = dfs(root->right, p, q);
        if((lson && rson) || (root->val == p->val || root->val == q->val) && (lson || rson))
        {
            ans = root;
        }

        return lson || rson ||  (root->val == p->val || root->val == q->val);

    }


    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {
        dfs(root, p, q);
        return ans;
    }
};