题目链接 题意: n个节点,给定每一个节点的子树(包含自己)的节点个数.每一个节点假设有子节点必定大于等于2.求这种数是否存在 n (1 ≤ n ≤ 24). 分析: 用类似DP的思路,从已知開始.这题的已知显然是叶子,那么从叶子開始考虑. 如今给一个节点,子树节点数为x.那么从叶子中找x-1个就可以.之后再来一个y.不放设y <= x,这时候就有两种选择,尽量选1或者尽量选x.分析一下:首先明确一点.无论怎样选择,之后能用的点的和是一定的.假设尽量选小的,那么会使得选过之后的点数小的比較少.假…

D. Happy Tree Party Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/593/problem/D Description Bogdan has a birthday today and mom gave him a tree consisting of n vertecies. For every edge of the tree i, some number xi was w…

D. Happy Tree Party     Bogdan has a birthday today and mom gave him a tree consisting of n vertecies. For every edge of the tree i, some number xi was written on it. In case you forget, a tree is a connected non-directed graph without cycles. After…

C. Propagating tree Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/383/problem/C Description Iahub likes trees very much. Recently he discovered an interesting tree named propagating tree. The tree consists of n nodes numb…

D. Water Tree Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/343/problem/D Description Mad scientist Mike has constructed a rooted tree, which consists of n vertices. Each vertex is a reservoir which can be either empty or…

F. st-Spanning Tree 题目连接: http://codeforces.com/contest/723/problem/F Description You are given an undirected connected graph consisting of n vertices and m edges. There are no loops and no multiple edges in the graph. You are also given two distinct…

C. Xor-tree Time Limit: 1 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/430/problem/C Description Iahub is very proud of his recent discovery, propagating trees. Right now, he invented a new tree, called xor-tree. After this new revolu…

C. Propagating tree Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/383/problem/C Description Iahub likes trees very much. Recently he discovered an interesting tree named propagating tree. The tree consists of n nodes numb…

D. Tricky Function Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 codeforces.com/problemset/problem/429/D Description Iahub and Sorin are the best competitive programmers in their town. However, they can't both qualify to an important contest. The sele…

Water Tree 给出一棵树,有三种操作: 1 x:把以x为子树的节点全部置为1 2 x:把x以及他的所有祖先全部置为0 3 x:询问节点x的值 分析: 昨晚看完题,马上想到直接树链剖分,在记录时间戳时需要记录一下出去时的时间戳,然后就是很裸很裸的树链剖分了. 稳稳的黄名节奏,因为一点私事所以没做导致延迟了 (ps:后来想了一下,不用树链剖分直接dfs序维护也行...) #include <set> #include <map> #include <list> #i…