P. T. Tigris is a student currently studying graph theory. One day, when he was studying hard, GS appeared around the corner shyly and came up with a problem: Given a graph with n nodes and m undirected weighted edges, every node having one of two co…

Description P. T. Tigris is a student currently studying graph theory. One day, when he was studying hard, GS appeared around the corner shyly and came up with a problem: Given a graph with n nodes and m undirected weighted edges, every node having o…

[la P5031&hdu P3726] Graph and Queries Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Problem Description You are given an undirected graph with N vertexes and M edges. Every vertex in this graph has an integer v…

题目来源:HDU 3726 Graph and Queries 题意:见白书 思路:刚学treap 參考白皮书 #include <cstdio> #include <cstring> #include <cstdlib> using namespace std; struct Node { Node *ch[2]; int r; int v; int s; Node(int v): v(v) { ch[0] = ch[1] = NULL; r = rand(); s…

https://vjudge.net/problem/HDU-4467 大概就是,设一个块大小T 对于度数<=T的点,设为1类点,在改变颜色的时候暴力查询与其相邻点,更新答案 对于度数>T的点,设为2类点,分别维护与其相邻的颜色为0/1的点之间的边权和(记录与每个点相连的所有2类点,然后在任意点(注意2类点也要)改变颜色时维护一下与其相连2类点的这个值),改变颜色的时候根据维护的值O(1)可以计算出对答案的修改 说的再简单一点,1类点由自身去更新其他,2类点由其他去更新自身..复杂度很容易发现…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=4467 题意:给定n个点m条边的无向图,点被染色(黑0/白1),边带边权.然后q个询问.询问分为两种: Change u:把点u的颜色反转(黑变白,白变黑),Asksum a b(a,b的值为0/1):统计所以边的权值和,边的两个点满足一个点的颜色为a,一个点的颜色为b. 思路:考虑暴力的做法.修改可以做法O(1),但是查询就得O(m).所以总复杂度为O(m*q)会TLE.然后考虑图分块.参考HDU…

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=4034 Problem Description Everyone knows how to calculate the shortest path in a directed graph. In fact, the opposite problem is also easy. Given the length of shortest path between each pair of vertexe…

Graph Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65768/65768 K (Java/Others)Total Submission(s): 1927    Accepted Submission(s): 965 Problem Description Everyone knows how to calculate the shortest path in a directed graph. In fact, the…

[题目链接] http://bestcoder.hdu.edu.cn/contests/contest_showproblem.php?cid=663&pid=1002 [题意] 给定一个有向图,若干个询问,问从u走k步到达各个顶点的概率. 其中除法化为乘逆元. [思路] 设f[i][j]表示到达i点走了j步的概率,则有转移式: f[i][j]=sigma{ f[pre(i)][j-1]/out[pre(i)] } 其中pre为有向图上的前一个节点,out[u]为u的出度大小. 构造矩阵后使用矩…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=4034 题目分类:图论 题意:n个顶点,然后给出从i到j的最短路径长度,求至少需要哪些边 第二组样例 第三组样例: 题目分析: 判断 a[i][j]==a[i][k]+a[k][j](详看代码) 代码: #include<bits/stdc++.h> using namespace std; ][]; int main() { #ifndef ONLINE_JUDGE freopen("i…