题目链接 Fill a DP table such as the following bottom-up: DP[v][0] = the number of ways that the subtree rooted at vertex v has no black vertex. DP[v][1] = the number of ways that the subtree rooted at vertex v has one black vertex. The recursion pseudo…
B. 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 are color…
Appleman has a tree with n vertices. Some of the vertices (at least one) are colored black and other vertices are colored white. Consider a set consisting of k (0 ≤ k < n) edges of Appleman's tree. If Appleman deletes these edges from the tree, then…
题目链接: http://codeforces.com/contest/161/problem/D D. Distance in Tree time limit per test 3 secondsmemory limit per test 512 megabytes 问题描述 A tree is a connected graph that doesn't contain any cycles. The distance between two vertices of a tree is th…
题目链接: Magic boy Bi Luo with his excited tree Time Limit: 8000/4000 MS (Java/Others) Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 1037 Accepted Submission(s): 298 Problem Description Bi Luo is a magic boy, he also has a migic…
Karen and Supermarket 感觉就是很普通的树形dp. dp[ i ][ 0 ][ u ]表示在 i 这棵子树中选择 u 个且 i 不用优惠券的最小花费. dp[ i ][ 1 ][ u ]表示在 i 这棵子树中选择 u 个且 i 用优惠券的最小花费. 注意这个转移总的合起来是O(n ^ 2)的. #include<bits/stdc++.h> #define LL long long #define fi first #define se second #define mk…
Code: #include<bits/stdc++.h> #define ull unsigned long long #define MOD 1000000007 #define ll long long #define maxn 120000 using namespace std; void setIO(string s) { string in=s+".in"; string out=s+".out"; freopen(in.c_str(),&…
