题目:Bear and Clique Distances 描述:共有N个点,前1—K个点任意两点之间有一条无向边,边的权值为X,再任意给M条边(u,v,w)(不重复),求任意一点到其余各点的最短路. 分析: 1.最短路算法(usual Dijkstra)+一点小变形(a little twist) 2.trick:设置一个变量upd=1;因为前K个点之前两两是连通的,所以当第一次到前K个点中任一点(假设为u)时,就可以更新得到前K个点的距离(除了u)d[i](i<=k)为d[u]+X. 即:1-…

CodeChef Sum of distances(分治) 题目大意 有一排点,每个点 i 向 \(i + 1, i + 2, i + 3\) 分别连价值为 \(a_i,b_i,c_i\) 的有向边,问两两间最短路之和 数据范围 \(1 \le n \le 10^5\) 解题思路 这种题已经从新颖变成套路了(唉) 考虑分治,很容易发现如果断掉连续的三个点那么图就不再联通,我们从中间找三个点,然后分别向两边跑最短路,设点 i 到三点最短距离为 \(x_1,x_2,x_3\),三点到 j 最短距离为…

C. Bear and String Distance time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Limak is a little polar bear. He likes nice strings - strings of length n, consisting of lowercase English letter…

C. Bear and String Distance 题目连接: http://www.codeforces.com/contest/628/problem/C Description Limak is a little polar bear. He likes nice strings - strings of length n, consisting of lowercase English letters only. The distance between two letters is…

C. Bear and String Distance time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Limak is a little polar bear. He likes nice strings — strings of length n, consisting of lowercase English letter…

第三弾が始まる! codechef problems 第三弹 一.Motorbike Racing 题面 It's time for the annual exciting Motorbike Race in Byteland. There are N motorcyclists taking part in the competition. Johnny is watching the race. At the present moment (time 0), Johnny has taken…

3514: Codechef MARCH14 GERALD07加强版 Time Limit: 60 Sec  Memory Limit: 256 MBSubmit: 1288  Solved: 490[Submit][Status][Discuss] Description N个点M条边的无向图,询问保留图中编号在[l,r]的边的时候图中的联通块个数. Input 第一行四个整数N.M.K.type,代表点数.边数.询问数以及询问是否加密.接下来M行,代表图中的每条边.接下来K行,每行两个整数L…

F. Bear and Fair Set time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Limak is a grizzly bear. He is big and dreadful. You were chilling in the forest when you suddenly met him. It's very u…

UVA - 11324 The Largest Clique 题意:求一个节点数最大的节点集,使任意两个节点至少从一个可以到另一个 同一个SCC要选一定全选 求SCC 缩点建一个新图得到一个DAG,直接DP行了 这个新图不需要判重边,重边就是真实存在 // // main.cpp // 最大团 // // Created by Candy on 02/11/2016. // Copyright © 2016 Candy. All rights reserved. // #include <ios…

B. Clique Problem time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The clique problem is one of the most well-known NP-complete problems. Under some simplification it can be formulated as f…