用链表构造一颗AVL的样子，不需要排序

#include 
using namespace std;
struct TreeNode {
      int val;
      TreeNode *left;
      TreeNode *right;
      TreeNode(int x) : val(x), left(NULL), right(NULL) {}
  };
  struct ListNode {
      int val;
      ListNode *next;
      ListNode() : val(0), next(nullptr) {}
      ListNode(int x) : val(x), next(nullptr) {}
  };
class Solution {
public:
    TreeNode* create(vector& nums, int low, int high){
        if(low > high)  return NULL;
        int mid = (high + low)/2;
        TreeNode* root = new TreeNode(nums[mid]);
        root->left = create(nums, low, mid-1);
        root->right = create(nums, mid+1, high);
        return root;
    }
    TreeNode* sortedArrayToBST(vector& nums) {
        return create(nums, 0, nums.size()-1);
    }
};
int main()
{
    Solution CT;
    ListNode head = new ListNode(0);
    cin>>head;
    vector ans;
    while(head){
       ans.pushback(head->next);
       head=head->next;
    }
    TreeNode res = new TreeNode(0);
           res=CT.sortedArrayToBST(ans);
    
    
}