/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
public:
	TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {
		if (root == nullptr || root == p || root == q) {
			return root;
		}

		TreeNode* leftResult = lowestCommonAncestor(root->left, p, q);
		TreeNode* rightResult = lowestCommonAncestor(root->right, p, q);

		if (leftResult != nullptr && rightResult != nullptr) {
			return root;
		}

		return leftResult != nullptr ? leftResult : rightResult;
	}
};