Tree - 随笔分类 - _fukua

codeforces 567 E. President and Roads dijkstra + 求图的桥

摘要：题意：给出一个图，n <= 10^5，给出起点s和终点t 有向边，每花费一个单位的钱可以选择一条边，把它的边权-1，但是边权必须>0, 比如边权为w，最多花费w-1，边权变为1，但是不能把边权变为0 现在要选择一条最短路从s到t 题目保证s到t至少有一条路问这个图 1.哪些边是一定会经过的 2. 阅读全文

posted @ 2017-08-31 02:05 _fukua 阅读(269) 评论(0) 推荐(0)

SPOJ Query on a tree 树链剖分水题

摘要：You are given a tree (an acyclic undirected connected graph) withNnodes, and edges numbered 1, 2, 3...N-1.We will ask you to perfrom some instructions... 阅读全文

posted @ 2015-10-15 18:47 _fukua 阅读(215) 评论(0) 推荐(0)

CF109 C. Lucky Tree 并查集

摘要：Petya loves lucky numbers. We all know that lucky numbers are the positive integers whose decimal representations contain only the lucky digits4and7. ... 阅读全文

posted @ 2015-10-14 17:58 _fukua 阅读(435) 评论(0) 推荐(0)

CF 191C Fools and Roads lca 或者树链剖分

摘要：They say that Berland has exactly two problems, fools and roads. Besides, Berland hasncities, populated by the fools and connected by the roads. All B... 阅读全文

posted @ 2015-10-13 13:18 _fukua 阅读(466) 评论(0) 推荐(0)

CF 486D vailid set 树形DP

摘要：As you know, an undirected connected graph withnnodes andn - 1edges is called atree. You are given an integerdand a tree consisting ofnnodes. Each nod... 阅读全文

posted @ 2015-10-13 12:23 _fukua 阅读(311) 评论(0) 推荐(0)

hdu 5444 Elven Postman 二叉树

摘要：Time Limit: 1500/1000 MS (Java/Others)Memory Limit: 131072/131072 K (Java/Others)Problem DescriptionElves are very peculiar creatures. As we all know,... 阅读全文

posted @ 2015-09-14 17:03 _fukua 阅读(263) 评论(0) 推荐(0)

CF 337D Book of Evil 树形DP 好题

摘要：Paladin Manao caught the trail of the ancient Book of Evil in a swampy area. This area containsnsettlements numbered from 1 ton. Moving through the sw... 阅读全文

posted @ 2015-08-30 22:40 _fukua 阅读(257) 评论(0) 推荐(0)

CF 274B Zero Tree 树形DP

摘要：Atreeis a graph withnvertices and exactlyn - 1edges; this graph should meet the following condition: there exists exactly one shortest (by number of e... 阅读全文

posted @ 2015-08-28 23:04 _fukua 阅读(375) 评论(0) 推荐(0)

CF 461B Appleman and Tree 树形DP

摘要：Appleman has a tree withnvertices. Some of the vertices (at least one) are colored black and other vertices are colored white.Consider a set consistin... 阅读全文

posted @ 2015-08-28 17:46 _fukua 阅读(260) 评论(0) 推荐(0)

CF 500D New Year Santa Network tree 期望好题

摘要：New Year is coming in Tree World! In this world, as the name implies, there arencities connected byn - 1roads, and for any two distinct cities there a... 阅读全文

posted @ 2015-08-27 23:13 _fukua 阅读(373) 评论(0) 推荐(0)

CF 161D Distance in Tree 树形DP

摘要：一棵树，边长都是1，问这棵树有多少点对的距离刚好为k令tree(i)表示以i为根的子树dp[i][j][1]:在tree（i）中，经过节点i，长度为j，其中一个端点为i的路径的个数dp[i][j][0]:在tree(i)中，经过节点i，长度为j，端点不在i的路径的个数则目标：∑(dp[i][k][0... 阅读全文

posted @ 2015-08-27 19:47 _fukua 阅读(314) 评论(0) 推荐(0)

CF 369C . Valera and Elections tree dfs 好题

摘要：C. Valera and ElectionsThe city Valera lives in is going to hold elections to the city Parliament.The city hasndistricts andn - 1bidirecti... 阅读全文

posted @ 2015-08-24 23:35 _fukua 阅读(328) 评论(0) 推荐(0)

CF 501C Misha and Forest 好题

摘要：C. Misha and ForestLet's define a forest as a non-directed acyclic graph (also without loops and parallel edges). One day Misha played... 阅读全文

posted @ 2015-08-24 15:56 _fukua 阅读(275) 评论(0) 推荐(0)

随笔分类 - Tree