Trail free response answer 4

The Trail problem from the 2010 AP Computer Science Exam is typical of free response problems that test arrays. The problem requires you to find the minimum and maximum in an array and access 2 elements of an array for each loop run.

Review the Trail free response problem with AP CS Tutor Brandon Horn.

Trail Part (a): isLevelTrailSegment

public boolean isLevelTrailSegment(int start, int end)
 {
  int minElevation = markers[start];
  int maxElevation = markers[start];

  for (int i = start + 1; i <= end; i++)
  {
   if (markers[i] < minElevation)
    minElevation = markers[i];

   if (markers[i] > maxElevation)
    maxElevation = markers[i];
  }

  return maxElevation - minElevation <= 10;
 }

Trail Part (b): isDifficult

public boolean isDifficult()
 {
  int significantChanges = 0;

  for (int i = 1; i < markers.length; i++)
   if (Math.abs(markers[i - 1] - markers[i]) >= 30)
    significantChanges++;

  return significantChanges >= 3;
 }