首页 > ACM题库 > HDU-杭电 > HDU 1712 ACboy needs your help-背包问题-[解题报告] c-sharp
2013
12-21

HDU 1712 ACboy needs your help-背包问题-[解题报告] c-sharp

ACboy needs your help

问题描述 :

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?

输入:

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.

输出:

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

样例输入:

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

样例输出:

3
4
6

//分组背包,看背包九讲
/*
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]}
*/
#include<iostream>
#include<cstdio>
using namespace std;
int a[101][101];
int n,m;
int dp[101]; //dp[i]表示用i天的时间做功课得到的最大收益
int max(int a,int b)
{
	return a>b?a:b;
}
void solve(int x)
{
	int i,j;
	for(i=m;i>=0;i--)
		for(j=1;j<=m;j++)    //对于每个分组里物品
			if(i>=j)
			dp[i]=max(dp[i],dp[i-j]+a[x][j]);
}
int main()
{
	while(scanf("%d%d",&n,&m)!=EOF&&!(n==0&&m==0))
	{
		int i,j;
		for(i=0;i<n;i++)
			for(j=1;j<=m;j++)
				scanf("%d",&a[i][j]);
			memset(dp,0,sizeof(dp));
			for(i=0;i<n;i++)
				solve(i);
			printf("%d/n",dp[m]);
	}
	return 0;
}

解题报告转自:http://blog.csdn.net/scnujack/article/details/6300881


  1. 第一题是不是可以这样想,生了n孩子的家庭等价于n个家庭各生了一个1个孩子,这样最后男女的比例还是1:1