#include <stdio.h>
#include <stdlib.h>


struct Interval
{
   float start;
   float finish;
   float value;
};

struct Intervals
{
   struct Interval * items;
   int number;
};

struct Intervals read_intervals(char * filename)
{
   struct Intervals result;
   result.number = 0;
   result.items = 0;

   FILE * handle = fopen(filename, "rb");
   if (handle == 0)
   {
      printf("cannot open %s\n", filename);
      return result;
   }

   fscanf(handle, "%d", &(result.number));
   result.items = malloc(sizeof(struct Interval) * (1 + result.number));
//   printf("number = %d\n", result.number);

   result.items[0].start = 0;
   result.items[0].finish = 0;
   result.items[0].value = 0;
   int counter;
   for (counter = 1; counter <= result.number; counter++)
   {
      float start, finish, value; 
      fscanf(handle, "%f %f %f", & start, & finish, & value);
      result.items[counter].start = start;
      result.items[counter].finish = finish;
      result.items[counter].value = value;
//      printf("%3d: start = %5.1f,   finish = %5.1f,   value = %5.1f\n", counter, start, finish, value);
      if (finish < result.items[counter-1].finish)
      {
         printf("error, intervals are not sorted\n");
         exit(1);
      }
   }

   return result;
}


int * compute_last_complete(struct Intervals intervals)
{
   int * last_complete = malloc(sizeof(int) * (1+intervals.number));
   last_complete[0] = 0;
   int counter, second_counter;
   for (counter = 1; counter <= intervals.number; counter++)
   {
      float start = intervals.items[counter].start;
      second_counter = counter - 1;
      while(1)
      {
         float finish = intervals.items[second_counter].finish;
         if (finish <= start)
         {
            last_complete[counter] = second_counter;
//            printf(" last_complete[%d] = %d\n", counter, second_counter);
            break;
         }
         second_counter--;
      }
   }
   return last_complete;
}
   
   
float wis(struct Intervals intervals)
{
   int * last_complete = compute_last_complete(intervals);
   float * solutions = malloc(sizeof(float) * (1+ intervals.number));
   solutions[0] = 0;
   int counter;
   for (counter = 1; counter <= intervals.number; counter++)
   {
      float solution_without = solutions[counter - 1];
      float value = intervals.items[counter].value;
      float solution_with = solutions[last_complete[counter]] + value;
      
      float best_value = solution_without;
      if (solution_with > best_value) best_value = solution_with;
      solutions[counter] = best_value;
//      printf("counter %4d: solution_without = %6.1f, solution_with = %6.1f, best = %6.1f\n",
//            counter, solution_without, solution_with, best_value);
   }

   float result = solutions[intervals.number];
   free(last_complete);
   free(solutions);
   return result;
}


int main()
{
   struct Intervals intervals = read_intervals("wis1.txt");

   float f = wis(intervals);
   printf("    wis = %f\n", f);

   free(intervals.items);
   return 0; 
}