hdu-1712 ACboy needs your help

ACboy needs your help

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)

Problem Description

ACboy has N courses this term, and he plans to spend at most M days on study.Of course,the profit he will gain from different course depending on the days he spend on it.How to arrange the M days for the N courses to maximize the profit?

 

Input

The input consists of multiple data sets. A data set starts with a line containing two positive integers N and M, N is the number of courses, M is the days ACboy has.
Next follow a matrix A[i][j], (1<=i<=N<=100,1<=j<=M<=100).A[i][j] indicates if ACboy spend j days on ith course he will get profit of value A[i][j].
N = 0 and M = 0 ends the input.

 

Output

For each data set, your program should output a line which contains the number of the max profit ACboy will gain.

 

Sample Input

2 2 1 2 1 3 2 2 2 1 2 1 2 3 3 2 1 3 2 1 0 0

 

Sample Output

3 4 6

 

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题解：

分组背包问题：

for 所有的组k

    for v=V..0

        for 所有的i属于组k

            f[v]=max{f[v],f[v-c[i]]+w[i]}

注意循环的顺序，v在i里面，保证每组最多只有一个物品被选

#include<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstdio>
using namespace std;
int f[110],w[110][110];
int get()
{
	int ans=0,f=1;char ch=getchar();
	while(!isdigit(ch)) {if(ch=='-') f=-1;ch=getchar();}
	while(isdigit(ch)) {ans=ans*10+ch-'0';ch=getchar();}
	return ans*f;
}
void init(int m)
{
	fill(f,f+m+1,0);
}
int main()
{
	int n,m;
	while(1)
	{
		n=get();m=get();
		if(n==0&&m==0)
		  return 0;
		for(int i=1;i<=n;i++)
		  for(int j=1;j<=m;j++)
		    w[i][j]=get();
		init(m);
		for(int i=1;i<=n;i++)
		  for(int j=m;j>=0;j--)
		    for(int k=0;k<=j;k++)
		      f[j]=max(f[j],f[j-k]+w[i][k]);
		printf("%d
",f[m]);
	}
	return 0;
}