首页 > ACM题库 > HDU-杭电 > HDU 4283-You Are the One-动态规划-[解题报告]HOJ
2015
05-23

HDU 4283-You Are the One-动态规划-[解题报告]HOJ

You Are the One

问题描述 :

  The TV shows such as You Are the One has been very popular. In order to meet the need of boys who are still single, TJUT hold the show itself. The show is hold in the Small hall, so it attract a lot of boys and girls. Now there are n boys enrolling in. At the beginning, the n boys stand in a row and go to the stage one by one. However, the director suddenly knows that very boy has a value of diaosi D, if the boy is k-th one go to the stage, the unhappiness of him will be (k-1)*D, because he has to wait for (k-1) people. Luckily, there is a dark room in the Small hall, so the director can put the boy into the dark room temporarily and let the boys behind his go to stage before him. For the dark room is very narrow, the boy who first get into dark room has to leave last. The director wants to change the order of boys by the dark room, so the summary of unhappiness will be least. Can you help him?

输入:

  The first line contains a single integer T, the number of test cases.  For each case, the first line is n (0 < n <= 100)
  The next n line are n integer D1-Dn means the value of diaosi of boys (0 <= Di <= 100)

输出:

  The first line contains a single integer T, the number of test cases.  For each case, the first line is n (0 < n <= 100)
  The next n line are n integer D1-Dn means the value of diaosi of boys (0 <= Di <= 100)

样例输入:

2
  
5
1
2
3
4
5

5
5
4
3
2
2

样例输出:

Case #1: 20
Case #2: 24

转载请注明出处,谢谢http://blog.csdn.net/acm_cxlove/article/details/7854526
      by—cxlove
题目:有一个队列,每个人有一个愤怒值D,如果他是第K个上场,不开心指数就为(K-1)*D。但是边上有一个小黑屋(其实就是个堆栈),可以一定程度上调整上场程序
http://acm.hdu.edu.cn/showproblem.php?pid=4283 
题目表示就看了好久,不能理解~~~Q_Q
注意是一定程度上调整,也就是入堆栈的顺序是确定的,第一反应的贪心肯定是错的
由于受堆栈的影响,总觉得要维护堆栈的状态,这样就挂了~~~~
其实是一个区间DP,dp[i][j]表示从第i个人到第j个人这段区间的最小花费(是只考虑这j-i+1个人,不需要考虑前面有多少人)
那么对于dp[i][j]的第i个人,就有可能第1个上场,也可以第j-i+1个上场。考虑第K个上场
即在i+1之后的K-1个人是率先上场的,那么就出现了一个子问题 dp[i+1][i+1+k-1-1]表示在第i个人之前上场的
对于第i个人,由于是第k个上场的,那么愤怒值便是val[i]*(k-1)
其余的人是排在第k+1个之后出场的,也就是一个子问题dp[i+k][j],对于这个区间的人,由于排在第k+1个之后,所以整体愤怒值要加上k*(sigma(i+k–j))

#include<iostream>
#include<cstdio>
#include<map>
#include<cstring>
#include<cmath>
#include<vector>
#include<algorithm>
#include<set>
#define inf 1<<27
#define N 105
#define Min(a,b) ((a)<(b)?(a):(b))
#define Max(a,b) ((a)>(b)?(a):(b))
#define pb(a) push_back(a)
#define LL long long
using namespace std;
int dp[105][105];
int val[105],sum[105];
int main(){
	int n,t,cas=0;
	scanf("%d",&t);
	while(t--){
		scanf("%d",&n);
		sum[0]=0;
		for(int i=1;i<=n;i++){
			scanf("%d",&val[i]);
			sum[i]=sum[i-1]+val[i];
		}
		memset(dp,0,sizeof(dp));
		for(int i=1;i<=n;i++)
			for(int j=i+1;j<=n;j++)
				dp[i][j]=inf;
		for(int l=1;l<=n-1;l++){
			for(int i=1;i<=n-l;i++){
				int j=i+l;
				//dp[i][j]=min(dp[i][j],dp[i+1][j]+sum[j]-sum[i]);
				for(int k=i;k<=j;k++)
					dp[i][j]=min(dp[i][j],val[i]*(k-i)+(k-i+1)*(sum[j]-sum[k])+dp[i+1][k]+dp[k+1][j]);
			}
		}
		printf("Case #%d: %d\n",++cas,dp[1][n]);
	}
	return 0;
}

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参考:http://blog.csdn.net/acm_cxlove/article/details/7964594