Reset ContentType Order in SharePoint 2010

//This is for Root Folder

   list.RootFolder.UniqueContentTypeOrder = null;

   list.RootFolder.Update();

//This is for Sub Folders

  SPFolderCollection folderCol = oList.RootFolder.SubFolders;

foreach (SPFolder folder in folderCol)

{

  folder.UniqueContentTypeOrder = null;

  folder.Update();

}