摘要： 原题链接在这里：https://leetcode.com/problems/arranging-coins/ 题目： You have a total of n coins that you want to form in a staircase shape, where every k-th ro 阅读全文

摘要： 原题链接在这里：https://leetcode.com/problems/valid-word-square/ 题目： Given a sequence of words, check whether it forms a valid word square. A sequence of word 阅读全文