北叶青藤

摘要： Given a rows x cols screen and a sentence represented by a list of words, find how many times the given sentence can be fitted on the screen. Note: A 阅读全文

摘要： Given a string S, find the number of different non-empty palindromic subsequences in S, and return that number modulo 10^9 + 7. A subsequence of a str 阅读全文