Решение задачи 1

#include <stdio.h>
#include <math.h>

void main(void)
{
   FILE *in, *out;
   int N, K[100], i, j, first, second, max;

   if ((in = fopen("INPUT.TXT", "rt")) == NULL)
    {
      fprintf(stderr, "Cannot open input file.\n");
      return;
    }
    fscanf(in, "%d", &N);
    for(i = 0; i < N; i++)
      fscanf(in, "%d", &K[i]);

   fclose(in);


    for(max = -1, i = 0; i < N-1; i++)
      for(j = i + 1; j < N; j++)
        if (max < abs(K[i] - K[j]))
          {
            max = abs(K[i] - K[j]);
            first = i;
            second = j;
          }

   if ((out = fopen("OUTPUT.TXT", "wt")) == NULL)
   {
      fprintf(stderr, "Cannot open output file.\n");
      return;
   }

   fprintf(out, "%d %d", K[first], K[second]);

   fclose(out);
}