leetcode[106]Construct Binary Tree from Inorder and Postorder Traversal

Given inorder and postorder traversal of a tree, construct the binary tree.

Note:
You may assume that duplicates do not exist in the tree.

/**
* Definition for binary tree
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
template<typename Iter>
void creatTree(TreeNode *&root,Iter inBeg,Iter inEnd, Iter posBeg,Iter posEnd)
{
if(inBeg==inEnd||posBeg==posEnd)
{
root=NULL;
return;
}
posEnd--;
root=new TreeNode(*posEnd);
Iter tmp=find(inBeg,inEnd,*posEnd);
int leftsize=tmp-inBeg;
creatTree(root->left,inBeg,tmp,posBeg,posBeg+leftsize);
creatTree(root->right,tmp+1,inEnd,posBeg+leftsize,posEnd);
}
TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder)
{
TreeNode *root;
creatTree(root,inorder.begin(),inorder.end(),postorder.begin(),postorder.end());
return root;
}
};