235. 二叉搜索树的最近公共祖先

/**
 * 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==p||root==q)
        return root;
    if(p->val<root->val&&q->val<root->val)
        return lowestCommonAncestor(root->left, p, q);
    if(p->val>root->val&&q->val>root->val)
        return lowestCommonAncestor(root->right,p,q);

         return root;
    }
    
};