Online JudgeProblem SetAuthorsOnline ContestsUser
Web Board
Home Page
F.A.Qs
Statistical Charts
Problems
Submit Problem
Online Status
Prob.ID:
Register
Update your info
Authors ranklist
Current Contest
Past Contests
Scheduled Contests
Award Contest
User ID:
Password:
  Register

【majuncheng】 AC 码

Posted by majuncheng at 2010-08-07 16:09:00 on Problem 1015
//poj 1015 相当经典的DP题。题意其实就是给一个n个整数的序列(可负),要求取出m个,使得这m个的整数和
//绝对值最小,而且Sum(di)+Sum(pi)最大。而且要求记录最优解的路径。
#include <iostream>
#include <algorithm>

using namespace std;

int n,m;
int d[205],p[205];  //本题的整数就是用d[i]-p[i]表示
//dp[i][j][k]记录算到第i个值,已经选j个值,和为k-20*m的最大Sum(di)+Sum(pi)。
//f[i][j][k]记录路径,表示相应的最后一个选的值。
int dp[205][25][40*20+1],f[205][25][40*20+1]; 
int ans[25];
int main()
{
    int t=0;
    while (scanf("%d%d",&n,&m) && n+m)
    {
          printf("Jury #%d\n",++t);
          for (int i=1;i<=n;i++) scanf("%d%d",&d[i],&p[i]);
		  memset(dp,-1,sizeof(dp));
		  memset(f,-1,sizeof(-1));
		  int zero=20*m,top=40*m;

		  
		  for (int i=0;i<=n;i++) dp[i][0][zero]=0;
		  for (int i=1;i<=n;i++)
			  for (int j=1;j<=m && j<=i;j++)
				  for (int k=0;k<=top;k++)
				  {
					  dp[i][j][k]=dp[i-1][j][k];f[i][j][k]=f[i-1][j][k]; //决策一,不取d[i]-p[i]
					  if ( k>=d[i]-p[i] && k-(d[i]-p[i])<=top && dp[i-1][j-1][k-(d[i]-p[i])]!=-1 && dp[i-1][j-1][k-(d[i]-p[i])]+d[i]+p[i]>=dp[i][j][k]) //决策二,取d[i]-p[i]
					  dp[i][j][k]=dp[i-1][j-1][k-(d[i]-p[i])]+d[i]+p[i],f[i][j][k]=i;
				  }

		 //找到绝对值最小的可行解
		 int i,j;
		 for (i=zero;i<=top;i++) if (dp[n][m][i]!=-1) break;
		 for (j=zero-1;j>=0;j--) if (dp[n][m][j]!=-1) break;
		 //printf("%d %d\n%d %d\n",i,dp[n][m][i],j,dp[n][m][j]);
	
		 if (j>=0)
		 if (i>top || i-zero > zero-j || i-zero==zero-j && dp[n][m][i]<dp[n][m][j]) i=j;
		 

		 //按记录的路径往回找,并放入ans中
		 int c=f[n][m][i],l=0,r=0;
		 for (int k=m;k>=1;k--)
		 {
			 l+=d[c],r+=p[c];
			 ans[k]=c;
			 i-=(d[c]-p[c]);
			 c=f[c-1][k-1][i];
		 }

		 printf("Best jury has value %d for prosecution and value %d for defence:\n",l,r);
		 //sort(ans+1,ans+1+m);
		 for (int i=1;i<=m;i++) printf(" %d",ans[i]);
		 printf("\n\n");
    }
   // system("pause");
    return 0;
}



Followed by:

Post your reply here:
User ID:
Password:
Title:

Content:

Home Page   Go Back  To top


All Rights Reserved 2003-2013 Ying Fuchen,Xu Pengcheng,Xie Di
Any problem, Please Contact Administrator