摘要： 题目如下： Given a string s. In one step you can insert any character at any index of the string. Return the minimum number of steps to make s palindrome. 阅读全文

摘要： 题目如下： There are n people, each person has a unique id between 0 and n-1. Given the arrays watchedVideos and friends, where watchedVideos[i] and friend 阅读全文

摘要： 题目如下： Given a string s formed by digits ('0' - '9') and '#' . We want to map s to English lowercase characters as follows: Characters ('a' to 'i') are 阅读全文