C++ :

#include<stdio.h>
#include<algorithm>
using namespace  std;
struct store
{
 int x;
 int feeds;
 int cents;
}a[101];
bool cmp(store al,store a2)
{
 return al.cents<a2.cents;
}
int main()
{
     int T,i,K,E,N,money;
     scanf("%d",&T);
     while(T--)
     {
          if(scanf("%d %d %d",&K,&E,&N)==EOF) return 0;
          for(i=0;i<N;++i)
          {
           scanf("%d %d %d",&a[i].x,&a[i].feeds,&a[i].cents);
           a[i].cents+=E-a[i].x;//单位点购买one feed ，费用值(运至E)
          }
          sort(a,a+N,cmp);
          money=0;
          for(i=0;i<N;i++)
          {
               if(a[i].feeds<=K)//购买feeds
               {
                money +=a[i].feeds*a[i].cents;
                K -=a[i].feeds;
               }
               else {money +=K*a[i].cents; break;}
          }
          printf("%d\n",money);
      }return 0;
}