HDU1712-ACboy needs your help

http://acm.hdu.edu.cn/showproblem.php?pid=1712

#include<cstdio>
#include<algorithm>
#define maxn 111
using namespace std;
int dp[maxn],a[maxn][maxn],i,j,k,n,m;
int main(void)
{
    while(scanf("%d%d",&n,&m),n||m)
    {
        for(i=1;i<=m;i++)
           dp[i]=0;
        for(i=1;i<=n;i++)
            for(j=1;j<=m;j++)
               scanf("%d",&a[i][j]);
        for(i=1;i<=n;i++)
            for(j=m;j>=1;j--)
                for(k=1;k<=j;k++)
                    dp[j]=max(dp[j],dp[j-k]+a[i][k]);
        printf("%d\n",dp[m]);
    }
    return 0;
}