程式語言 - LeetCode - C++ - 236. Lowest Common Ancestor of a Binary Tree

參考資訊：
https://www.cnblogs.com/grandyang/p/4641968.html

題目：


解答：

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

        TreeNode *l = lowestCommonAncestor(root->left, p, q);
        TreeNode *r = lowestCommonAncestor(root->right, p, q);

        if (l && r) {
            return root;
        }

        return l ? l : r;
    }
};