//判断二叉树是否是平衡搜索树

//中序遍历判断即可

/*struct TreeNode {    int val;    struct TreeNode *left;    struct TreeNode *right;    TreeNode(int x) :            val(x), left(NULL), right(NULL) {    }};*/class Checker {public:    bool checkBST(TreeNode* root) {        stack
     
       s;        TreeNode *pNode = root;        vector
      
        data;        while (pNode != NULL || !s.empty())        {            while (pNode != NULL)            {                s.push(pNode);                pNode = pNode->left;            }            if (!s.empty())            {                pNode = s.top();                data.push_back(pNode->val);                s.pop();                pNode = pNode->right;            }        }        for (size_t i = 0; i < data.size()-1; i++)        {            if (data[i] > data[i + 1])                return false;        }        return true;    }    };