HDU1520 Anniversary party —— 树形DP
来源:互联网 发布:使命召唤 知乎 编辑:程序博客网 时间:2024/05/17 03:17
题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1520
Anniversary party
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 12366 Accepted Submission(s): 5009
Problem Description
There is going to be a party to celebrate the 80-th Anniversary of the Ural State University. The University has a hierarchical structure of employees. It means that the supervisor relation forms a tree rooted at the rector V. E. Tretyakov. In order to make the party funny for every one, the rector does not want both an employee and his or her immediate supervisor to be present. The personnel office has evaluated conviviality of each employee, so everyone has some number (rating) attached to him or her. Your task is to make a list of guests with the maximal possible sum of guests' conviviality ratings.
Input
Employees are numbered from 1 to N. A first line of input contains a number N. 1 <= N <= 6 000. Each of the subsequent N lines contains the conviviality rating of the corresponding employee. Conviviality rating is an integer number in a range from -128 to 127. After that go T lines that describe a supervisor relation tree. Each line of the tree specification has the form:
L K
It means that the K-th employee is an immediate supervisor of the L-th employee. Input is ended with the line
0 0
L K
It means that the K-th employee is an immediate supervisor of the L-th employee. Input is ended with the line
0 0
Output
Output should contain the maximal sum of guests' ratings.
Sample Input
711111111 32 36 47 44 53 50 0
Sample Output
5
Source
Ural State University Internal Contest October'2000 Students Session
题解:
dp[u][state]:结点u其状态为state(0或1,即不放和放)的最大值。
状态转移:
1.如果当前结点不放,那么它的子结点放不放都行,所以两者取其大。
2.如果当前结点放,那么它的子节点只能不放。
代码如下:
#include <iostream>#include <cstdio>#include <algorithm>#include <cstring>#include <vector>#include <cmath>using namespace std;typedef long long LL;const int INF = 2e9;const LL LNF = 9e18;const int MOD = 1e9+7;const int MAXN = 1e4+10;int val[MAXN], hav_fa[MAXN], dp[MAXN][2];vector<int>son[MAXN];int dfs(int u){ dp[u][0] = 0; //不放,初始化为0 dp[u][1] = val[u]; //放,初始化为本身的值 for(int i = 0; i<son[u].size(); i++) { int v = son[u][i]; dfs(v); //递归其子树 dp[u][0] += max(dp[v][0], dp[v][1]); //如果不放,那么它的子节点放不放都行,所以取其大。 dp[u][1] += dp[v][0]; //如果放,那么它的子节点不能放 } return max(dp[u][0], dp[u][1]); //返回最大值}int main(){ int n; while(scanf("%d",&n)!=EOF) { for(int i = 1; i<=n; i++) son[i].clear(), hav_fa[i] = 0; for(int i = 1; i<=n; i++) scanf("%d",&val[i]); int u, v; while(scanf("%d%d",&v,&u) && (v || u)) { son[u].push_back(v); hav_fa[v] = 1; } for(int i = 1; i<=n; i++) //找到根节点,然后深搜 if(!hav_fa[i]) cout<< dfs(i) <<endl; }}
阅读全文
0 0
- HDU1520 Anniversary party —— 树形DP
- hdu1520——Anniversary party(树形dp)
- hdu1520 Anniversary party 树形dp
- HDU1520:Anniversary party(树形DP)
- hdu1520 Anniversary party(树形DP)
- hdu1520 Anniversary party (树形dp)
- hdu1520 Anniversary party 【树形dp】
- HDU1520 Anniversary party(树形DP)
- 【树形DP】HDU1520-Anniversary party
- HDU1520 Anniversary party 树形DP
- HDU1520 Anniversary party[树形DP]
- HDU1520 Anniversary party 树形DP
- hdu1520-树形dp-Anniversary party
- hdu1520 Anniversary party 树形dp
- HDU1520-Anniversary party(树形dp)
- 树形dp Anniversary party(HDU1520)
- hdu1520 Anniversary party(poj2342,树形dp)
- HDU1520 Anniversary party(树形DP)
- kafka开发笔记
- 笔记:时间戳和日期相互转换
- 笔记:css3 transition 实现div宽度以中心为原点向两边伸长
- avformat_open_input函数分析
- WOJ1008-Feeding Animals(II)
- HDU1520 Anniversary party —— 树形DP
- 微信公众平台 多媒体文件上传接口调试工具
- node-sass安装出错问题解决
- String intern
- POJ 3469 Dual Core CPU (最小割)
- HTML和css3
- app:processDebugManifest 错误
- 关于POI导出表格
- 解决Jococo代码覆盖率 安装包后,执行指令闪退