HDU 1024

态转移方程: dp[i][j]=max{dp[i][j-1]+A[j],dp[i-1][t]+a[j] (i-1<=t<n-m+i) }

#include <stdio.h>
#include <string.h>
int num[1000050] ,pre[1000050] ,now[1000050];
int main ()
{
    long int m ,n ,max_pre;
    while (scanf("%d%d",&m,&n) != EOF)
    {
          for (int i = 1 ;i <= n ;i++)
               scanf("%d",&num[i]);   
          memset(pre ,0 ,sizeof (pre)) ;
          memset(now ,0 ,sizeof (now)) ;
          for (int i = 1 ;i <= m ;i++)
          {
               max_pre = -9999999;
               for (int j = i ;j <= n ;j++)
               {
                     //now[j] = max(now[j - 1] + num[j] ,pre[j - 1] + num[j]);
                     now[j] = (now[j - 1] > pre[j - 1] ? now[j - 1] : pre[j - 1]) + num[j];
                     pre[j - 1] = max_pre;
                     if (now[j] > max_pre)
                     max_pre = now[j];   
               }
          }
          printf("%ld\n",max_pre);
    }
    return 0;
}