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NC51166. Jury Compromise

描述

In Frobnia, a far-away country, the verdicts in court trials are determined by a jury consisting of members of the general public. Every time a trial is set to begin, a jury has to be selected, which is done as follows. First, several people are drawn randomly from the public. For each person in this pool, defence and prosecution assign a grade from 0 to 20 indicating their preference for this person. 0 means total dislike, 20 on the other hand means that this person is considered ideally suited for the jury. 
Based on the grades of the two parties, the judge selects the jury. In order to ensure a fair trial, the tendencies of the jury to favour either defence or prosecution should be as balanced as possible. The jury therefore has to be chosen in a way that is satisfactory to both parties. 
We will now make this more precise: given a pool of n potential jurors and two values di (the defence's value) and pi (the prosecution's value) for each potential juror i, you are to select a jury of m persons. If J is a subset of {1,..., n} with m elements, then D(J ) = sum(dk) k belong to J 
and P(J) = sum(pk) k belong to J are the total values of this jury for defence and prosecution. 
For an optimal jury J , the value |D(J) - P(J)| must be minimal. If there are several jurys with minimal |D(J) - P(J)|, one which maximizes D(J) + P(J) should be selected since the jury should be as ideal as possible for both parties. 
You are to write a program that implements this jury selection process and chooses an optimal jury given a set of candidates.

输入描述

The input file contains several jury selection rounds. Each round starts with a line containing two integers n and m. n is the number of candidates and m the number of jury members.
These values will satisfy , and of course m<=n. The following n lines contain the two integers pi and di for i = 1,...,n. A blank line separates each round from the next.
The file ends with a round that has n = m = 0.

输出描述

For each round output a line containing the number of the jury selection round ('Jury #1', 'Jury #2', etc.).
On the next line print the values D(J ) and P (J ) of your jury as shown below and on another line print the numbers of the m chosen candidates in ascending order. Output a blank before each individual candidate number.
Output an empty line after each test case.

示例1

输入:

4 2 
1 2 
2 3 
4 1 
6 2 
0 0 

输出:

Jury #1
Best jury has value 6 for prosecution and value 4 for defence:
 2 3

原站题解

上次编辑到这里,代码来自缓存 点击恢复默认模板

C++14(g++5.4) 解法, 执行用时: 77ms, 内存消耗: 17680K, 提交时间: 2019-11-14 07:36:01

#include <cstring>
#include <algorithm>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <vector>
#define ll long long
#define rep(i,a,b)	for(int i=(a);i<=(b);++i)
using namespace std;
const int M=205;
vector <int> path;
int m,n,f[25][1005],d[M][25][1005],a[M],b[M],T,sum1,sum2,ans;
void get_path(int i,int j,int k)
{
	if(j==0)	return ;
	int ls=d[i][j][k];
	get_path(ls-1,j-1,k-(a[ls]-b[ls]));
	path.push_back(ls);
	sum1+=a[ls];sum2+=b[ls];
}
int main()
{
	while(cin>>n>>m&&n)
	{
		memset(f,0xcf,sizeof f);
		rep(i,1,n)	scanf("%d%d",&a[i],&b[i]);
		f[0][400]=0;//平移! 
		rep(i,1,n)
		{
			rep(j,0,m)
				rep(k,0,800)	d[i][j][k]=d[i-1][j][k];
			for(int j=m;j>=1;--j)
				rep(k,0,800)
				{
					if(k-(a[i]-b[i])<0||k-(a[i]-b[i])>800)	continue;
					if(f[j][k]<f[j-1][k-(a[i]-b[i])]+a[i]+b[i])
					{
						f[j][k]=f[j-1][k-(a[i]-b[i])]+a[i]+b[i];
						d[i][j][k]=i;
					}
				}
		}
		ans=0;
		rep(k,0,400)
		{
			if(f[m][400+k]>=0&&f[m][400+k]>=f[m][400-k])
			{
				ans=400+k;
				break;
			}
			if(f[m][400-k]>=0)
			{
				ans=400-k;
				break;
			}
		}
		sum1=0;sum2=0;
		path.clear();
		get_path(n,m,ans);
		printf("Jury #%d\n", ++T);
		printf("Best jury has value %d for prosecution and value %d for defence:\n",sum1,sum2);
		for (int i=0;i<path.size();++i) printf(" %d",path[i]);
		printf("\n\n");
	}
	return 0;
}

C++11(clang++ 3.9) 解法, 执行用时: 34ms, 内存消耗: 1760K, 提交时间: 2020-04-01 23:17:32

#include<bits/stdc++.h>
using namespace std;
struct node
{
	int a,b;
}q[205];
int dp[25][855];
vector <int> ans[25][855];int d1=0,p1=0;
int main()
{
	int n,m,cnt=1;
	while(~scanf("%d%d",&n,&m)){
		if(n==m&&n==0)	break;
		for(int i=1;i<=n;i++){
			scanf("%d%d",&q[i].a,&q[i].b);
		}
		memset(dp,-1,sizeof dp);
		for(int i=1;i<=m;i++)
			for(int j=0;j<=m*40;j++)
				ans[i][j].clear();
		int mi=1e9;dp[0][20*m]=0;
		for(int i=1;i<=n;i++){
			int d=q[i].a-q[i].b,t=q[i].a+q[i].b;
			for(int h=m;h>=1;h--)
				for(int j=0;j<40*m;j++)
					if(dp[h-1][j]!=-1)
						if(dp[h][j+d]<dp[h-1][j]+t){
							dp[h][j+d]=dp[h-1][j]+t;
							ans[h][j+d]=ans[h-1][j];
							ans[h][j+d].push_back(i);
						}
		}
		for(int i=0;;i++){
			if(dp[m][20*m-i]!=-1||dp[m][20*m+i]!=-1){
				mi=i;break;
			}
		}
		mi=dp[m][mi+m*20]>dp[m][m*20-mi]?mi:-mi;
		printf("Jury #%d\n",cnt++);
		d1=dp[m][mi+m*20]+mi;d1/=2;
		p1=dp[m][mi+m*20]-mi;p1/=2;
		printf("Best jury has value %d for prosecution and value %d for defence:\n",d1,p1);
		for(int i=0;i<m;i++)
			printf("%d ",ans[m][mi+m*20][i]);printf("\n\n");
	}
}

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