Circular Coloring 将n个0,m个1进行圆周排列,定义一个排列的权值为圆上所有相邻且相同的数字组成一段的段长的乘积,询问断环成链所有方案的权值之和,\(n,m\leq 5000\). 解 因为问题与区间划分有关,直接计数不好做,对序列上考虑,不妨设\(f[i][j]\)为前i个元素(相同的)划分j段的权值和,显然有 \[f[i][j]=\sum_{k=0}^{i-1}f[k][j-1](i-k)\] 这个方程是\(O(n^3)\),于是考虑优化,两种方法 法一: \[f[i][j…

题意: 给一个环,环上有n+m个点.给n个点染成B,m个点染成W.求所有染色情况的每段长度乘积之和. 题解: 染成B的段数和染成W的段数是一样的(因为是环). 第一段是可以移动的,例如BBWWW移动为BWWWB. 所以处理两个方程:b[i][j]代表把j分成i段的乘积和且第一段不能移动:f[i][j]代表把j分成i段的乘积和且第一段可以移动. 那么枚举分成的段数,对于当前枚举分成i段,答案就为:f[i][n]*b[i][m]+f[i][m]*b[i][n]. 问题是方程怎么转移了. 对于b[i]…

A - Easy $h$-index 后缀扫一下 #include <bits/stdc++.h> using namespace std; #define ll long long #define N 200010 int n; ll arr[N]; inline int work() { ll sum = ; ; --i) { sum += arr[i]; if (sum >= i) return i; } ; } int main() { while (scanf("%d…

1. 问题的现象 比如在webConfig中定义了一个viewResolver public class WebConfig extends WebMvcConfigurerAdapter { //配置JSP视图解析器 @Bean public ViewResolver viewResolver() { InternalResourceViewResolver resolver = new InternalResourceViewResolver(); resolver.setPrefix("W…

From:http://bradforj287.blogspot.com/2010/11/efficient-circular-buffer-in-java.html import java.util.NoSuchElementException; /** * Thread safe fixed size circular buffer implementation. Backed by an array. * * @author brad */ public class ArrayCircul…

今天在将一个项目迁移至ASP.NET Core的过程中遭遇一个循环依赖问题,错误信息如下: A circular dependency was detected for the service of type 'CNBlogs.Application.Interfaces.ITagService' 一开始以为是项目之间的引用关系引起的,在project.json中找来找去,一无所获. 后来从构造函数下手,才发现问题所在. 实现ITagService的类TagService的构造函数是这么定义的:…

题目链接 http://codeforces.com/contest/711/problem/C Description ZS the Coder and Chris the Baboon has arrived at Udayland! They walked in the park where n trees grow. They decided to be naughty and color the trees in the park. The trees are numbered wit…

题意:给括号匹配涂色,红色蓝色或不涂,要求见原题,求方案数 区间DP 用栈先处理匹配 f[i][j][0/1/2][0/1/2]表示i到ji涂色和j涂色的方案数 l和r匹配的话,转移到(l+1,r-1) 不匹配,i的匹配p一定在l和r之间,从p分开转移 听说用记忆化搜索比较快,可以像树形DP那样写记忆化搜索,也可以传统的四个参数那样写 用循环+条件判断,简化状态转移的枚举 注意细节 见代码 #include<iostream> #include<cstdio> #include&l…

C. Coloring Trees   ZS the Coder and Chris the Baboon has arrived at Udayland! They walked in the park where n trees grow. They decided to be naughty and color the trees in the park. The trees are numbered with integers from 1 to n from left to right…

Circular progress bar in Unity 3D - UnityScripthttp://stackoverflow.com/questions/22662706/circular-progress-bar-in-unity-3d-unityscript Another approach would be to use the NGUI plugin and use an UISprite with radial fill…