D - Chloe and pleasant prizes 链接 http://codeforces.com/contest/743/problem/D 题面 Generous sponsors of the olympiad in which Chloe and Vladik took part allowed all the participants to choose a prize for them on their own. Christmas is coming, so sponso…

题目:http://codeforces.com/contest/1153/problem/D 题意:给你一棵树,每个节点有一个操作,0代表取子节点中最小的那个值,1代表取子节点中最大的值,叶子节点的话就是自己置一个值,有k个子节点,那么每个子节点的值范围 就是1-k,1-k只能用一次 思路:贪心不好取,我肯定是要排列完才知道当前的值是哪个,但是我可以知道当前节点应该是取子节点中排名第几的那个,从而推出根节点1的排名,然后再输出就行,因为是要从 子节点那里递归上来,所以我们采取树形dp #inc…

http://codeforces.com/contest/816/problem/E 题意: 去超市买东西,共有m块钱,每件商品有优惠卷可用,前提是xi商品的优惠券被用.问最多能买多少件商品? 思路: 第一件商品使用优惠券不需要前提,别的都是需要的,然后这样就形成了一棵以1为根的树. 这样,很容易想到是树形dp. d[u][j][0/1]表示以u为根的子数中选择j件商品所需的最少花费,0/1表示u商品是否能用优惠券. 解释一下代码中的sz[],它所代表的是以u为根的子树的结点数. 当我们现在访…

B. Chloe and the sequence 题目链接 http://codeforces.com/contest/743/problem/B 题面 Chloe, the same as Vladik, is a competitive programmer. She didn't have any problems to get to the olympiad like Vladik, but she was confused by the task proposed on the ol…

传送门 Description Chloe, the same as Vladik, is a competitive programmer. She didn't have any problems to get to the olympiad like Vladik, but she was confused by the task proposed on the olympiad. Let's consider the following algorithm of generating a…

E. Vladik and cards 题目链接 http://codeforces.com/contest/743/problem/E 题面 Vladik was bored on his way home and decided to play the following game. He took n cards and put them in a row in front of himself. Every card has a positive integer number not e…

题目链接 D. Appleman and Tree time limit per test :2 seconds memory limit per test: 256 megabytes input :standard input output:standard output Appleman has a tree with n vertices. Some of the vertices (at least one) are colored black and other vertices a…

D. Nauuo and Circle •参考资料 [1]:https://www.cnblogs.com/wyxdrqc/p/10990378.html •题意 给出你一个包含 n 个点的树,这 n 个点编号为 1~n: 给出一个圆,圆上放置 n 个位置,第 i 个位置对应树中的某个节点,并且不重复: 求在圆上还原这棵树后,使得边不相交的总方案数: •题解 ①为何每一颗子树一定是连续的一段圆弧? 假设不是连续的圆弧,如图所示: 为了使 x 接到树上,必然会有 x-y 或 x-z 相连的边,这样…

Famil Door's City map looks like a tree (undirected connected acyclic graph) so other people call it Treeland. There are n intersections in the city connected by n - 1 bidirectional roads. There are m friends of Famil Door living in the city. The i-t…

D. Chloe and pleasant prizes time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Generous sponsors of the olympiad in which Chloe and Vladik took part allowed all the participants to choose a…