题目如下: Given a positive integer n, return the number of all possible attendance records with length n, which will be regarded as rewardable. The answer may be very large, return it after mod 109 + 7. A student attendance record is a string that only c…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 正则表达式 统计 日期 题目地址:https://leetcode.com/problems/student-attendance-record-i/#/description 题目描述 You are given a string representing an attendance record for a student. The record…

Given a positive integer n, return the number of all possible attendance records with length n, which will be regarded as rewardable. The answer may be very large, return it after mod 109 + 7. A student attendance record is a string that only contain…

Given a positive integer n, return the number of all possible attendance records with length n, which will be regarded as rewardable. The answer may be very large, return it after mod 109 + 7. A student attendance record is a string that only contain…

problem 551. Student Attendance Record I 题意: solution: class Solution { public: bool checkRecord(string s) { ; ; for(auto ch:s) { if('A'==ch) { ) return false;// cntL = ;// } else if('L' == ch) { ) return false;// } ;// } return true; } }; 理解题意很简单,重要…

给定一个正整数 n,返回长度为 n 的所有可被视为可奖励的出勤记录的数量. 答案可能非常大,你只需返回结果mod 109 + 7的值.学生出勤记录是只包含以下三个字符的字符串:    1.'A' : Absent,缺勤    2.'L' : Late,迟到    3.'P' : Present,到场如果记录不包含多于一个'A'(缺勤)或超过两个连续的'L'(迟到),则该记录被视为可奖励的.示例:输入: n = 2输出: 8 解释:有8个长度为2的记录将被视为可奖励:"PP" , &qu…

[LeetCode]522. Longest Uncommon Subsequence II 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址:https://leetcode.com/problems/longest-uncommon-subsequence-ii/description/ 题目描述: Given a list of strings, you…

Given a positive integer n, return the number of all possible attendance records with length n, which will be regarded as rewardable. The answer may be very large, return it after mod 109 + 7. A student attendance record is a string that only contain…

Given a positive integer n, return the number of all possible attendance records with length n, which will be regarded as rewardable. The answer may be very large, return it after mod 109 + 7. A student attendance record is a string that only contain…

Given an index k, return the kth row of the Pascal's triangle. For example, given k = 3, Return [1,3,3,1]. Note: Could you optimize your algorithm to use only O(k) extra space? 思路:最简单的方法就是依照[Leetcode]Pascal's Triangle 的方式自顶向下依次求解,但会造成空间的浪费.若仅仅用一个vect…