LeetCode: 106_Construct Binary Tree from Inorder and Postorder Traversal | 根据中序和后序遍历构建二叉树 | Medium

要求：根据中序和后序遍历序列构建一棵二叉树

代码如下：

struct TreeNode {
    int            val;
    TreeNode    *left;
    TreeNode    *right;
    TreeNode(int x): val(x),left(NULL), right(NULL) {}
};

typedef vector<int>::iterator Iter;

TreeNode *buildTreeFromInorderPostorder(vector<int> &inorder, vector<int> &postorder)
{
    return buildBinaryTreeResur(inorder.begin(), inorder.end(), postorder.begin(), postorder.end());
}

TreeNode *buildBinaryTreeResur(Iter istart, Iter iend, Iter pstart, Iter pend)
{
    if (istart == iend || pstart == pend)
        return NULL;
    int ival = *(pend-1);
    Iter ptemp = find(istart, iend, ival);
    TreeNode *res = new TreeNode(ival);
    res->left = buildBinaryTreeResur(istart, ptemp, pstart, pstart+(ptemp-istart));
    res->right = buildBinaryTreeResur(ptemp+1, iend, pstart+(ptemp-istart), pend-1);
    return res;
}