Leetcode---Construct Binary Tree from Inorder and Postorder Traversal

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

给后序序列和中序序列，求二叉树。

这个怎么说呢，和上一道题如出一辙，只不过是顺序变了，简单！

TreeNode * f(vector<int> &inorder, vector<int> &postorder, int inl,int inr,int postl, int postr){
    int n=inr-inl+1;
    if(n==0)
        return NULL;
    int i=0;
    for(;i<=n-1;i++){
        if(inorder[inl+i]==postorder[postr])
            break;
    }
    TreeNode * root=new TreeNode(inorder[inl+i]);
    root->left=f(inorder,postorder,inl,inl+i-1,postl,postl+i-1);
    root->right=f(inorder,postorder,inl+i+1,inr,postl+i,postr-1);
    return root;
}
TreeNode *buildTree(vector<int> &inorder, vector<int> &postorder) {
    return f(inorder,postorder,0,inorder.size()-1,0,postorder.size()-1);
}