fatttcat

摘要： Given a fixed length array arr of integers, duplicate each occurrence of zero, shifting the remaining elements to the right. Note that elements beyond 阅读全文

摘要： Given an array A of strings made only from lowercase letters, return a list of all characters that show up in all strings within the list (including d 阅读全文

摘要： Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. A mapping of digit to le 阅读全文

摘要： Numbers can be regarded as product of its factors. For example, Write a function that takes an integer n and return all possible combinations of its f 阅读全文

摘要： Given two integers n and k, return all possible combinations of knumbers out of 1 ... n. Example: use DFS (backtracking) time = O(k * C(n, k)), space 阅读全文

摘要： Design a simplified version of Twitter where users can post tweets, follow/unfollow another user and is able to see the 10 most recent tweets in the u 阅读全文

摘要： A string S represents a list of words. Each letter in the word has 1 or more options. If there is one option, the letter is represented as is. If ther 阅读全文

摘要： We are given two arrays A and B of words. Each word is a string of lowercase letters. Now, say that word b is a subset of word a if every letter in b  阅读全文

摘要： Given a string S, we can transform every letter individually to be lowercase or uppercase to create another string. Return a list of all possible stri 阅读全文

摘要： We have a collection of rocks, each rock has a positive integer weight. Each turn, we choose the two heaviest rocks and smash them together. Suppose t 阅读全文