HDU 4003 Find Metal Mineral (树形dp)
来源:互联网 发布:李雪儿的网络歌曲 编辑:程序博客网 时间:2024/04/30 17:31
Find Metal Mineral
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65768/65768 K (Java/Others)Total Submission(s): 3463 Accepted Submission(s): 1610
Problem Description
Humans have discovered a kind of new metal mineral on Mars which are distributed in point‐like with paths connecting each of them which formed a tree. Now Humans launches k robots on Mars to collect them, and due to the unknown reasons, the landing site S of all robots is identified in advanced, in other word, all robot should start their job at point S. Each robot can return to Earth anywhere, and of course they cannot go back to Mars. We have research the information of all paths on Mars, including its two endpoints x, y and energy cost w. To reduce the total energy cost, we should make a optimal plan which cost minimal energy cost.
Input
There are multiple cases in the input.
In each case:
The first line specifies three integers N, S, K specifying the numbers of metal mineral, landing site and the number of robots.
The next n‐1 lines will give three integers x, y, w in each line specifying there is a path connected point x and y which should cost w.
1<=N<=10000, 1<=S<=N, 1<=k<=10, 1<=x, y<=N, 1<=w<=10000.
In each case:
The first line specifies three integers N, S, K specifying the numbers of metal mineral, landing site and the number of robots.
The next n‐1 lines will give three integers x, y, w in each line specifying there is a path connected point x and y which should cost w.
1<=N<=10000, 1<=S<=N, 1<=k<=10, 1<=x, y<=N, 1<=w<=10000.
Output
For each cases output one line with the minimal energy cost.
Sample Input
3 1 11 2 11 3 13 1 21 2 11 3 1
Sample Output
32HintIn the first case: 1->2->1->3 the cost is 3;In the second case: 1->2; 1->3 the cost is 2;
Source
The 36th ACM/ICPC Asia Regional Dalian Site —— Online Contest
Recommend
lcy | We have carefully selected several similar problems for you: 4001 4007 4006 4009 4008
题意:给出结点数n,起点s,机器人数k,然后n-1行给出相互连接的两个点,还有这条路线的价值,问你最小花费。
题解:
dp[i][j]表示对于以 i 结点为根结点的子树,放 j 个机器人所需要的权值和。
当 j=0 时表示放了一个机器人下去,遍历完结点后又回到 i 结点了。状态转移方程类似背包。
当 j=0 时表示放了一个机器人下去,遍历完结点后又回到 i 结点了。状态转移方程类似背包。
AC代码:
#include<bits/stdc++.h>using namespace std;struct Node{ int now,next,val;}tree[20005];int dp[10005][15];//dp[i][j]表示对于以i结点为根结点的子树,放j个机器人所需要的权值和。int head[10005];int n,s,k,len;void addedge(int x,int y,int w){ tree[len].now = y; tree[len].val = w; tree[len].next = head[x]; head[x] = len++;}void dfs(int root,int fa){ for(int i = head[root];i!=-1;i = tree[i].next) { int son = tree[i].now; if(son == fa) continue; dfs(son,root); for(int j = k;j>=0;j--) { //先将dp[son][0]放进树中,因为 dp[son][0]是表示用一个机器人去走完所有子树,最后又回到 pos这个节点,所以花费要乘以2 dp[root][j]+=dp[son][0]+2*tree[i].val; for(int l = 1;l<=j;l++)//再找到更优的,就是分组背包 dp[root][j] = min(dp[root][j],dp[root][j-l]+dp[son][l]+l*tree[i].val); } }}int main(){ int i,x,y,w; while(~scanf("%d%d%d",&n,&s,&k)) { len = 0; memset(head,-1,sizeof(head)); memset(dp,0,sizeof(dp)); for(i = 1;i<n;i++) { scanf("%d%d%d",&x,&y,&w); addedge(x,y,w); addedge(y,x,w); } dfs(s,0); printf("%d\n",dp[s][k]); } return 0;}TLE代码....用vector去存...
#include<bits/stdc++.h>#include<vector>using namespace std;vector<int> V[20010];//dp[i][j]表示对于以i结点为根结点的子树,放j个机器人所需要的权值和。 int dp[20010][30];int val[20010];int n,s,k;void dfs(int root,int fa){for(int i=0; i< V[root].size();i++){int son=V[root][i];if(son==fa)continue;dfs(son,root);for(int j=k;j>=0;--j){//先将dp[son][0]放进树中,因为dp[son][0]是表示用一个机器人去走完所有子树,最后又回到 pos这个节点,所以花费要乘以2 dp[root][j]+=dp[son][0]+ 2*val[i];for(int l=1;l<=j;l++)//再找到更优的 {dp[root][j] = min(dp[root][j],dp[root][j-1]+dp[son][l]+l*val[i]);}}}}int main(){int x,y;while(~scanf("%d%d%d",&n,&s,&k)){for(int i=0;i<n;i++) V[i].clear();memset(dp,0,sizeof(dp));for(int i=0;i<n-1;i++){scanf("%d%d%d",&x,&y,&val[i]);V[x].push_back(y);V[y].push_back(x);}dfs(s,0);printf("%d\n",dp[s][k]);}return 0;}
2 0
- HDU 4003 Find Metal Mineral 树形DP
- hdu 4003 Find Metal Mineral 树形DP
- HDU-4003 Find Metal Mineral 树形dp
- HDU 4003--Find Metal Mineral(树形dp)
- hdu 4003 Find Metal Mineral (树形dp)
- hdu 4003 Find Metal Mineral(树形DP)
- hdu 4003 Find Metal Mineral(树形DP+分组背包)
- hdu 4003 Find Metal Mineral(树形dp+分组背包)
- HDU 4003 Find Metal Mineral (树形dp)
- HDU 4003 Find Metal Mineral (树形dp)
- hdu 4003 Find Metal Mineral(树形dp+分组背包)
- hdu 4003 Find Metal Mineral (树形背包dp)
- hdu 4003 Find Metal Mineral (树形dp+分组背包)
- hdu 4003 Find Metal Mineral 【树形dp,分组背包】
- hdu 4003 Find Metal Mineral 树形dp+分组背包
- hdu 4003 Find Metal Mineral (树形dp+背包)
- HDU 4003 Find Metal Mineral(树形dp + 分组背包)
- HDU 4003 Find Metal Mineral (树形DP+分组背包)
- 当科技让我们不是人了
- 从一元一次方程到伽罗瓦理论-读后
- python新手常见的报错提示
- hadoop2 作业执行过程之作业提交
- poj3009Curling 2.0
- HDU 4003 Find Metal Mineral (树形dp)
- 固定位数随机数
- 入职三个月有感
- <设计模式19>备忘录模式
- JS获取本周周一 周日日期、本季度、本月、上月的开端日期、停止日期
- Makefile规则
- 管道和FIFO
- 前端技术书籍
- hadoop高级应用-搜索提示