leetcode/src/s0236_lowest_common_ancestor_of_a_binary_tree.cpp

#include "s0236_lowest_common_ancestor_of_a_binary_tree.hpp"

TreeNode* S0236::lowestCommonAncestor(TreeNode* root, TreeNode* p,
                                      TreeNode* q) {
  if (root == nullptr || root == p || root == q) return root;
  TreeNode* left = lowestCommonAncestor(root->left, p, q);
  TreeNode* right = lowestCommonAncestor(root->right, p, q);
  if (left != nullptr && right != nullptr) {
    return root;
  } else if (left != nullptr) {
    return left;
  } else if (right != nullptr) {
    return right;
  } else {
    return nullptr;
  }
}