/**
* 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 == NULL)
{
return NULL;
}
if (root == p || root == q)
{
return root;
}
TreeNode* leftLCA = lowestCommonAncestor(root->left, p, q);
TreeNode* rightLCA = lowestCommonAncestor(root->right, p, q);
if (leftLCA != NULL && rightLCA != NULL)
{
return root;
}
if (leftLCA != NULL)
{
return leftLCA;
}
return rightLCA;
}
};