/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
struct TreeNode *reConstructcore(vector<int> pre, vector<int> in)
{
if(pre.size()==0||in.size()==0) return NULL;
TreeNode *root=Constructcore(pre,in,0,(int )pre.size()-1,0,(int )in.size()-1);//size?-1?
return root;
}
TreeNode *Constructcore(vector<int> pre, vector<int> in,int startPre,int endPre,int startIn,int endIn )
{
if(pre.size()||in.size()<=0)
return NULL;
int len=pre.size();
int temp=pre[startPre];
TreeNode*head=new TreeNode(temp);
int i,pos;
if (startPre == endPre){
if (startIn == endIn &&pre[startPre] == in[startIn])
return root;
}
for(i=startIn;i<=endIn;i++)
{
if(temp==in[i])
{
pos=i;
break;
}
}
int left_len=(pos-1)-startIn+1;
int right_len=endIn-(pos+1)+1;
if(left_len>0)
{
head->left=Constructcore( pre, in,startPre,pos-1,startPre,pos-1 );
}
if(right_len>0)
head->right=Constructcore( pre, in,pos+1,endPre,pos+1,endIn);
return head;
}
};