There are many data structures (DS) in the topic of strings like: suffix-trees, suffix-arrays, tries etc. Do we have to learn all of these DS in the interview point of view? Also do we have to learn algorithms like KMP, Rabin-Karp, Burrows-Wheeler transform etc.? If there is no need to learn all of them, can someone please tell what DS and algorithms to be focussed on, in this topic?