#define N (10)  //set the total station
#define OIL_PER_KM (1)
#define INIT_OIL (5)
#define MAX_CONTAINER (100)
struct station
{
 float dist;
 float price;
};

float curr;
struct station st[N];

void init_station()
{
 //int i;
 curr = INIT_OIL;

 //initilize the station information
 st[0].dist = 0;
 st[N].price = MAX_LONG;
 //otherinformation should be filled according to the actually.
}
// 0 -- for increment always
// 1 == exist decrement,but the low state's prices is higher the the from state
// -1 -- the last station
int check_state(int from,int to,int &ret)
{
 int i ;
 int retValue = 0;
 if(from == to) {
  return -1;
 }
 for(i = from ; i < to ; i ++) {
  if(st[i].price > st[i + 1].price) {
   if(st[i + 1].price > st[from].price) {
    retValue = 1;   
   } else {
    retValue = 2;    
   }
   ret = i + 1;
   break;
  }
 }

 return retValue;
}
float get_oli(int from,int to)
{
 int i;
 float total = 0.0;
 if(from == to) {
  return total;
 }
 for(i =from ; i <= to ; i ++) {
  total += st[i].dist;
 }

 return (total * OIL_PER_KM);
}
float try_search()
{
 int i ,j, retValue,newIndex;
 float tmp, cost = 0;
  do{
  curr -= st[i].dist * OIL_PER_KM;

  if(st[i].price >= st[i + 1].price) {   
   tmp = get_oli(i,i+1);
   cost += (tmp - curr) * st[i].price;
   curr = tmp;
   i ++;
  } else {
   for(j = i + 1; j < N - 1; j ++) {
    tmp = MAX_CONTAINER;
    tmp -= st[j].dist * OIL_PER_KM;

    if(tmp < 0) {
     break;
    }
   }
   //this is the station we can reach,if the
   j --;
   retValue = check_state(i,j,newIndex);
   if(retValue == 0) {    
    cost += (MAX_CONTAINER - curr) * st[i].price;
    curr = MAX_CONTAINER ;
    i ++;
   } else if(retValue == 1) {
    tmp = get_oli(i,newIndex);
    cost += (tmp - curr) * st[i].price;
    curr = tmp;
    i = newIndex;
   } else {
    tmp = ( st[i +1].dist * OIL_PER_KM - curr);
    if(tmp > 0 ) {
     cost += tmp * st[i].price;
    }
    i ++;
   }
  }
 }while(i < N -1);
  return cost;
}