以前序确定节点，以中序确定节点左右子节点
class Solution {
public:
int n=0;
unordered_maphashmap;
TreeNode* dsf(vector& preorder, vector& inorder,int pre_l,int pre_r,int in_l,int in_r){
cout<left=dsf(preorder,inorder ,pre_l+1,pre_l+size_l, in_l,in_innode-1);
tree->right=dsf(preorder,inorder ,pre_r-size_r+1,pre_r, in_innode+1,in_r);
return tree;
}
TreeNode* buildTree(vector& preorder, vector& inorder) {
if(preorder.empty())return NULL;
n=preorder.size();
for(int i=0;i
