leetcode[105]Construct Binary Tree from Preorder and Inorder Traversal

Given preorder and inorder 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 preBeg,Iter preEnd,Iter inBeg,Iter inEnd)
{
    if (preBeg==preEnd||inBeg==inEnd)
    {
        root=NULL;
        return;
    }
    root=new TreeNode(*preBeg);
    vector<int>::iterator tmp=find(inBeg,inEnd,*preBeg);
    int leftsize=tmp-inBeg;
    creatTree(root->left, preBeg+1,preBeg+leftsize+1,inBeg,tmp);
    creatTree(root->right, preBeg+leftsize+1,preEnd,tmp+1,inEnd);
}
TreeNode *buildTree(vector<int> &preorder, vector<int> &inorder) 
{
    TreeNode *root;
    creatTree(root,preorder.begin(),preorder.end(),inorder.begin(),inorder.end());
    return root;
}
/*
TreeNode * creatTree(vector<int>::iterator preBeg,vector<int>::iterator preEnd,vector<int>::iterator inBeg,vector<int>::iterator inEnd)
{
    if (preBeg==preEnd||inBeg==inEnd)
    {
        return NULL;
    }
    TreeNode *root=new TreeNode(*preBeg);
    vector<int>::iterator tmp=find(inBeg,inEnd,*preBeg);
    int leftsize=tmp-inBeg;
    root->left=creatTree(preBeg+1,preBeg+leftsize+1,inBeg,tmp);
    root->right=creatTree(preBeg+leftsize+1,preEnd,tmp+1,inEnd);
    return root;
}
TreeNode *buildTree(vector<int> &preorder, vector<int> &inorder) 
{
    return creatTree(preorder.begin(),preorder.end(),inorder.begin(),inorder.end());
}
*/
};