题意 题目链接 Sol 一道很简单的树形dp,然而被我写的这么长 分别记录下距离为\(1/2\)的点数,权值和,最大值.以及相邻儿子之间的贡献. 树形dp一波.. #include<bits/stdc++.h> #define Fin(x) {freopen(x, "r", stdin);} #define int long long using namespace std; const int MAXN = 2e5 + 10, mod = 10007; inline in…
题目:https://www.luogu.org/problemnew/show/P2634 今天刚学了点分治,做例题: 好不容易A了,结果发现自己写的是树形DP...(也不用找重心)(比点分治快) #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; typedef long long ll; ,inf=0x3f3f3f3…
P3047 [USACO12FEB]附近的牛Nearby Cows 题目描述 Farmer John has noticed that his cows often move between nearby fields. Taking this into account, he wants to plant enough grass in each of his fields not only for the cows situated initially in that field, but…
题目:https://www.luogu.org/problemnew/show/P1131 因为越高,调节一个影响到的越多,所以底下只要把子树间的差异消除了就行了,与其他部分的差异由更高的边调节. #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #define ll long long using namespace std; ; ],nxt[N<&l…
To 洛谷.1063 能量项链 题目描述 在Mars星球上,每个Mars人都随身佩带着一串能量项链.在项链上有N颗能量珠.能量珠是一颗有头标记与尾标记的珠子,这些标记对应着某个正整数.并且,对于相邻的两颗珠子,前一颗珠子的尾标记一定等于后一颗珠子的头标记.因为只有这样,通过吸盘(吸盘是Mars人吸收能量的一种器官)的作用,这两颗珠子才能聚合成一颗珠子,同时释放出可以被吸盘吸收的能量.如果前一颗能量珠的头标记为m,尾标记为r,后一颗能量珠的头标记为r,尾标记为n,则聚合后释放的能量为m*r*n(M…