I am integrating/syncronising three different API's in one application first API(1) will provide me the folder(folder(1)_id, folder(1)_name) second API will provide folder(folder(1)name, parent_folder(1)__id) I need to keep above in one table and need to compare with third API, if that contains same folder name as existing folder(folder(1)_name) then keep them as it is and if there are no folders with same name then add it from 1st and 2nd API and vice a versa. there is no limitation on number of folders I also need to keep track of all for future sync. what will be optimal way to do this in (i-phone)objective-c? I heard about the Hash-map, hash-table and Dictionary or I can simply use array for that, can anybody suggest easy/faster way to do this, any existing references? please.