#include <limits.h>
#include <stdlib.h>
#include <string.h>

void
compute_forward (const char *string, unsigned int len, int occ[UCHAR_MAX + 1])
{
  int i;

  memset (occ, 0, (UCHAR_MAX + 1) * sizeof (int));
  for (i = 0; i < len; i++)
    occ[(unsigned char) string[i]]++;
}

void
compute_backward (const char *string, unsigned int len, int occ[UCHAR_MAX + 1])
{
  int i;

  memset (occ, 0, (UCHAR_MAX + 1) * sizeof (int));
  for (i = len - 1; i >= 0; i--)
    occ[(unsigned char) string[i]]++;
}

int
sumup_no_abs (int occ_diff[UCHAR_MAX + 1])
{
  int sum;
  int i;

  sum = 0;
  for (i = 0; i <= UCHAR_MAX; i++)
    {
      int d = occ_diff[i];
      sum += (d >= 0 ? d : -d);
    }
  return sum;
}

int
sumup_abs (int occ_diff[UCHAR_MAX + 1])
{
  int sum;
  int i;

  sum = 0;
  for (i = 0; i <= UCHAR_MAX; i++)
    sum += abs (occ_diff[i]);
  return sum;
}