38. 外观数列 「外观数列」是一个整数序列,从数字 1 开始,序列中的每一项都是对前一项的描述.前五项如下: 1 11 21 1211 111221 1 被读作 "one 1" ("一个一") , 即 11. 11 被读作 "two 1s" ("两个一"), 即 21. 21 被读作 "one 2", "one 1" ("一个二" , "一个一"…

作者: 负雪明烛 id: fuxuemingzhu 公众号:负雪明烛 本文关键词:LeetCode,力扣,算法,算法题,外观数列,Count and Say,刷题群 目录 题目描述 题目大意 解题方法 解法一:循环 解法二:递归 刷题心得 日期 题目地址:https://leetcode.com/problems/count-and-say/#/description 题目描述 The count-and-say sequence is the sequence of integers with…

题目链接:1084 外观数列 (20 point(s)) 题目描述 外观数列是指具有以下特点的整数序列: d, d1, d111, d113, d11231, d112213111, - 它从不等于 1 的数字 d 开始,序列的第 n+1 项是对第 n 项的描述.比如第 2 项表示第 1 项有 1 个 d,所以就是 d1:第 2 项是 1 个 d(对应 d1)和 1 个 1(对应 11),所以第 3 项就是 d111.又比如第 4 项是 d113,其描述就是 1 个 d,2 个 1,1 个 3,…

Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique set of numbers. Ensure that numbers within the set are sorted in ascending order. Example 1…

Given a string S, you are allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrome you can find by performing this transformation. For example: Given "aacecaaa", return "aaacecaaa&qu…

Given a 2D board and a list of words from the dictionary, find all words in the board. Each word must be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same le…

Design a data structure that supports the following two operations: void addWord(word)bool search(word) search(word) can search a literal word or a regular expression string containing only letters a-z or .. A . means it can represent any one letter.…

There are a total of n courses you have to take, labeled from 0 to n - 1. Some courses may have prerequisites, for example to take course 0 you have to first take course 1, which is expressed as a pair: [0,1] Given the total number of courses and a l…

Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by…

Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find the maximum profit. You may complete at most k transactions. 解题思路: https://leetcode.com/discuss/18330/is-it-best-solution-with-o-n-o-1…