首先发现结果与需要改变的具体位置无关,只和需要改变的位置的个数有关,因此设f[i][j]表示选取了i个数字异或结果有j个1,只要分析接下来选择的数和这j个1有几个重合即可: 1. 三个数字全部重合,即$f[i][j+3]+=f[i-1][j]\cdot c(n-j,3)$ 2. 有两个数字重合,即$[i][j+1]+=f[i-1][j]\cdot c(n-j,2)\cdot j$ 3. 有一个数字重合,即$f[i][j-1]+=f[i-1][j]\cdot (n-j)\cdot c(j,2)$…

A - Age of Moyu 题意:给出一张图,从1走到n,如果相邻两次走的边的权值不同,花费+1, 否则花费相同,求最小花费 思路:用set记录有当前点的最小花费有多少种方案到达,然后最短路 #include<bits/stdc++.h> using namespace std; const int INF = 0x3f3f3f3f; ; struct Edge{ int to, nxt, val; Edge(){} Edge(int to, int nxt, int val):to(to…

Chamber of Secrets 题目连接: http://codeforces.com/problemset/problem/173/B Description "The Chamber of Secrets has been opened again" - this news has spread all around Hogwarts and some of the students have been petrified due to seeing the basilisk…

1.jstl.jar  servlet.jar支持 2.jsp引入标签库 <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%> <%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt"%> <%@ taglib prefix="fn" u…

Overview¶ A view is a “type” of Web page in your Django application that generally serves a specific function and has a specific template. For example, in a blog application, you might have the following views: Blog homepage – displays the latest few…

Treasure Exploration Time Limit: 6000MS   Memory Limit: 65536K Total Submissions: 8301   Accepted: 3402 Description Have you ever read any book about treasure exploration? Have you ever see any film about treasure exploration? Have you ever explored…

Django文档阅读-Day3 Writing your first Django app, part 3 Overview A view is a "type" of Web page in your Django application that generally serves a specific function and has a specific template. For example, in a blog application, you might have th…

A city's skyline is the outer contour of the silhouette formed by all the buildings in that city when viewed from a distance. Now suppose you are given the locations and height of all the buildings as shown on a cityscape photo (Figure A), write a pr…

De-mystifying Good Research and Good Papers By Fei-Fei Li, 2009.03.01 Please remember this: 1000+ computer vision papers get published every year! Only 5-10 are worth reading and remembering! Since many of you are writing your papers now, I thought t…

A city's skyline is the outer contour of the silhouette formed by all the buildings in that city when viewed from a distance. Now suppose you are given the locations and height of all the buildings as shown on a cityscape photo (Figure A), write a pr…