Node ReconstructTreeHelper(SubArray<int> preorder, SubArray<int> inorder,
Dictionary<int, int> inorderMapTable)
{
int rootVal = preorder[0];
int rootPos = inorderMapTable[rootVal] - inorder.Offset;
Node node = new Node { Id = rootVal };
int nodesToLeft = rootPos;
if (nodesToLeft > 0)
node.Left = ReconstructTreeHelper(preorder.SubArray(1, nodesToLeft),
inorder.SubArray(0, nodesToLeft), inorderMapTable);
int nodesToRight = inorder.Count - rootPos - 1;
if (nodesToRight > 0)
node.Right = ReconstructTreeHelper(preorder.SubArray(rootPos + 1, nodesToRight),
inorder.SubArray(rootPos + 1, nodesToRight), inorderMapTable);
return node;
}