摘要： In English, we have a concept called root, which can be followed by some other words to form another longer word - let's call this word successor. For 阅读全文

摘要： Given a non-empty array of integers, return the k most frequent elements. For example,Given [1,1,1,2,2,3] and k = 2, return [1,2]. Note: You may assum 阅读全文