存储名字和姓氏的算法和数据结构

Is there a efficient way to store first name and last name in data structure so that we can lookup using either first or last name? I would consider a binary search tree with first name. It would be efficient to search first name. But wouldnt be efficient when trying to search last name. we can also consider one more BST with last name. Any ideas to implement it efficiently?Is there a efficient way to store first name an