hdu 1712, multiple-choice knapsack,

reference:
6.4 knapsack in Algorithms(算法概论), Sanjoy Dasgupta University of California, San Diego Christos Papadimitriou University of California at Berkeley Umesh Vazirani University of California at Berkeley
the unbounded knapsack and 0-1 knapsack are both illuminatingly discussed in the reference book, in chapter 6 dynamic programming, strongly recommended. the multiple-choice knapsack and bounded knapsack are variants of 0-1 knapsack.
//

#include <cstdio>
#include <cstring>
#include <algorithm>

#define MAXSIZE 105
int dp[MAXSIZE]={0}, *p;
int profit[MAXSIZE];
int main() {
#ifndef ONLINE_JUDGE
    freopen("in.txt","r",stdin);
#endif
    int n,m,i,j,k;
    while(scanf("%d%d",&n,&m)==2 && n>0 && m>0) {
        memset(dp+1,0,(m+1)*sizeof(dp[0]));
        for(i=0;i<n;++i) {
            for(j=1;j<=m;++j) scanf("%d",&profit[j]);
            /*
            // 多重背包, unbounded knapsack
            for(j=1;j<=m;++j) {
                for(k=1;k<=j;++k) {
                    dp[j]=std::max(dp[j],profit[k]+dp[j-k]);
                }
            }*/
            // 分组背包, multiple choice knapsack
            for(j=m, p=dp+m;p!=dp;--p, --j) {
                for(k=1;k<=j;++k) {
                    if(*p<profit[k]+p[-k])
                    *p=profit[k]+p[-k];
                }
            }
        }
        printf("%d\n",dp[m]);
    }
    return 0;
}