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 pri…

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…

题目链接:http://codeforces.com/contest/743/problem/D 大致思路挺简单的就是找到一个父节点然后再找到其两个字节点总值的最大值. 可以设一个dp[x]表示x节点及以下节点能得到的最大值,由于dfs的顺序我们 可以边dfs边求解ans=max(dp[x]+dp[v],ans)(由于dfs是先查询完dp[v]的 左边的树,所以得到的dp[x]是在v节点左边的最大值),顺便记录一下每个节 点的sum值因为一个节点要么整个子树包括自己都要算或者不算. #inclu…

http://codeforces.com/problemset/problem/743/D 题意:求最大两个的不相交子树的点权和,如果没有两个不相交子树,那么输出Impossible. 思路:之前好像也做过这种类型的题目啊,知道是树形DP,但是不知道怎么保证两个不相交.看别人代码之后, 在DFS回溯的时候, void dfs(int u, int fa) { sum[u] = w[u]; for(int i = head[u]; ~i; i = edge[i].nxt) { int v = e…

http://codeforces.com/contest/743/problem/D 如果我们知道mx[1]表示以1为根节点的子树中,点权值的最大和是多少(可能是整颗树,就是包括了自己).那么,就可以O(n)扫一次各个点,对于每个点的儿子. 选出最大的两个mx[son],更新答案即可.(注意这个节点只有1个或者没有儿子,就要是-inf) 那么怎么得到这个mx[]呢? 可以知道mx[father] = max(所有的mx[son]) 最后还要看看是否能选择整个树,所以用dp[cur]表示以cur…

                                                            D. Chloe and pleasant prizes                                                            time limit per test 2 seconds                                                      memory limit per te…

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…

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 pri…

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 pri…

LightOJ 1033  Generating Palindromes(dp) 题目链接:http://acm.hust.edu.cn/vjudge/contest/view.action?cid=87730#problem/A 题目: Description By definition palindrome is a string which is not changed when reversed. "MADAM" is a nice example of palindrome.…