题目如下: We are given hours, a list of the number of hours worked per day for a given employee. A day is considered to be a tiring day if and only if the number of hours worked is (strictly) greater than 8. A well-performing interval is an interval of d…

Longest Palindromic Substring: Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. Example: Input: "babad" Output: "bab" Note: "aba" is also a valid answer. Exam…

题目: Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring. 题解: 第一种方法就是挨个检查,维护全局最长,时间复杂度为O(n3),会TLE. 代码如下:  1 public String longest…

Longest Palindromic Subsequence 题解 题目来源:https://leetcode.com/problems/longest-palindromic-subsequence/description/ Description Given a string s, find the longest palindromic subsequence's length in s. You may assume that the maximum length of s is 10…

2018-07-08 13:24:31 一.525. Contiguous Array 问题描述: 问题求解: 我们都知道对于subarray的问题,暴力求解的时间复杂度为O(n ^ 2),问题规模已经给出是50000量级,显然只能是O(n),至多O(nlogn)的复杂度. 本题使用DP和滑动数组都比较棘手,这才是最麻烦的地方,我们知道一般来说对于subarray的问题,dp和滑动数组是两大利器,但是本题这两个最实用的解法都不再适用,那么该如何解决呢? 其实想通了就是一个很简单的问题,本题是lo…

Three farmers rise at 5 am each morning and head for the barn to milk three cows. The first farmer begins milking his cow at time 300 (measured in seconds after 5 am) and ends at time 1000. The second farmer begins at time 700 and ends at time 1200.…

题目链接 题意:求[1,n]有多少个素数,1<=n<=10^11.时限为6000ms. 官方题解:一个模板题, 具体方法参考wiki或者Four Divisors. 题解:给出两种代码. 第一种方法Meisell-Lehmer算法只需265ms. 第二种方法不能运行但是能AC,只需35行. 第一种: //Meisell-Lehmer #include<cstdio> #include<cmath> using namespace std; #define LL long…

Milking Cows Three farmers rise at 5 am each morning and head for the barn to milk three cows. The first farmer begins milking his cow at time 300 (measured in seconds after 5 am) and ends at time 1000. The second farmer begins at time 700 and ends a…

题目:Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring. 题解:首先需要清楚什么是“回文“(不知道这个翻译对不对?)字符串!回文字符串关于某一个字符对称,在左右两边与中心相同距离的字符相等. 那么还需要…

Union Find算法基础 Union Find算法用于处理集合的合并和查询问题,其定义了两个用于并查集的操作: Find: 确定元素属于哪一个子集,或判断两个元素是否属于同一子集 Union: 将两个子集合并为一个子集 并查集是一种树形的数据结构,其可用数组或unordered_map表示: Find操作即查找元素的root,当两元素root相同时判定他们属于同一个子集:Union操作即通过修改元素的root(或修改parent)合并子集,下面两个图展示了id[6]由6修改为9的变化:   …