Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST.

class Solution {
public:
    TreeNode* createTree(vector<int>& nums,int left,int right)
    {
        if(left>right)
          return NULL;
          
        int mid = (left+right)>>1;
        TreeNode* leftNode = createTree(nums,left,mid-1);  //创建左子树
        TreeNode* rightNode = createTree(nums,mid+1,right);//创建右子树
        
        TreeNode* node = new TreeNode(nums[mid]);
        node->left = leftNode;
        node->right = rightNode;
        
        return node;
    }
    
    TreeNode* sortedListToBST(ListNode* head) {
        vector<int> nums;
        ListNode* p = head;
        while(p!=NULL)
        {
            nums.push_back(p->val);
            p = p->next;
        }
        return createTree(nums,0,nums.size()-1);
    }
};