/** * struct TreeNode { * int val; * struct TreeNode *left; * struct TreeNode *right; * }; */ class Solution { public: /** * * @param root TreeNode类 * @param o1 int整型 * @param o2 int整型 * @return int整型 */ int lowestCommonAncestor(TreeNode* root, int o1, int o2) { if (root == nullptr) return -1; if (root->val == o1 || root->val == o2) return root->val; int left_res = lowestCommonAncestor(root->left, o1, o2); int right_res = lowestCommonAncestor(root->right, o1, o2); if (left_res == -1) return right_res; // 若left为null,则在right if (right_res == -1) return left_res; // 若right为null,则在left // 二者都为null,则有一个节点在cur节点 return root->val; } };