/**
* Recursive function to sort array of integers using the Quick Sort Algorithm.
*
* @param array Array of integers to sort.
* @param begin The starting index in <code>array</code> of the range to be sorted.
* @param end The ending index in <code>array</code> of the range to be sorted.
*/
void sort(int[] array, int begin, int end) {
int[] arraycpy = new int[array.length];
for (int i = 0; i < array.length; i++) arraycpy[i] = array[i];
if (begin < end) {
// fibQuestion q = new fibQuestion(out, (new Integer(qIndex)).toString());
// Remember that Animal wants quotes around the question text
// q.setQuestionText("\"Which number in the array will be chosen as pivot index?\"");
// questions.addQuestion(q);
// out.println("{");
// questions.animalInsertQuestion(qIndex);
// out.println("}");
int pivIndex = partition(array, begin, end);
// After calling on partition, pivIndex is used to set the answer
// for the question
// And, remember that Animal wants quotes around the question answer
// q.setAnswer("\"" + arraycpy[pivIndex] + "\"");
// qIndex++;
sort(array, begin, pivIndex - 1);
sort(array, pivIndex + 1, end);
} else {
out.println("{");
out.println("highlightArrayCell on \"qarray\" position " + begin);
out.println("}");
}
}
/**
* Performs the section of the Quick Sort Algorithm which creates partitions.
*
* @param array The array of integers to be sorted.
* @param first The first index in <code>array</code> of the range to be partitioned.
* @param last The last index in <code>array</code> of the range to be partitioned.
*/
int partition(int[] array, int first, int last) {
int pivVal = array[first];
int up = first;
int down = last;
int tmp;
int lastIndex = array.length + 1;
fibQuestion q = null;
out.println("{");
out.println("moveArrayIndex \"lo\" to position " + first);
out.println("moveArrayIndex \"hi\" to position " + last);
out.print("arraySwap on \"qarray\" position " + first + " with " + lastIndex);
out.println(" within 500 ms");
out.println("}");
boolean question_at_end = false;
while (up < down) {
// The next two loops are "fakes", doing a preliminary pass to
// see if we need to generate a question
int up_dup = up;
int down_dup = down;
while ((array[up_dup] <= pivVal) && (up_dup < last)) up_dup++;
while ((array[down_dup] > pivVal) && (down_dup > first)) down_dup--;
if ((up_dup < down_dup)) {
q = new fibQuestion(out, (new Integer(qIndex)).toString());
// Remember that Animal wants quotes around the question text
q.setQuestionText("\"Which numbers in the array will swap next?\"");
questions.addQuestion(q);
out.println("{");
questions.animalInsertQuestion(qIndex);
out.println("}");
} else {
question_at_end = true;
q = new fibQuestion(out, (new Integer(qIndex)).toString());
// Remember that Animal wants quotes around the question text
q.setQuestionText("\"At what number in the array will the pointers meet?\"");
questions.addQuestion(q);
out.println("{");
questions.animalInsertQuestion(qIndex);
out.println("}");
}
while ((array[up] <= pivVal) && (up < last)) {
up++;
out.println("{");
out.println("moveArrayIndex \"lo\" to position " + up);
out.println("}");
}
while ((array[down] > pivVal) && (down > first)) {
down--;
out.println("{");
out.println("moveArrayIndex \"hi\" to position " + down);
out.println("}");
}
if (up < down) {
// And, remember that Animal wants quotes around the question answer
q.setAnswer(
"\""
+ array[up]
+ " "
+ array[down]
+ "\""
+ "\n"
+ "\""
+ array[down]
+ " "
+ array[up]
+ "\"");
qIndex++;
tmp = array[up];
array[up] = array[down];
array[down] = tmp;
out.println("{");
out.print("arraySwap on \"qarray\" position " + up + " with " + down);
out.println(" within 500 ms");
out.println("}");
}
}
// And, remember that Animal wants quotes around the question answer
// There was no swap but the pointers met
if (question_at_end) {
q.setAnswer("\"" + array[up] + "\"");
qIndex++;
}
if (first != down) {
// And, remember that Animal wants quotes around the question answer
// q.setAnswer("\"" + array[first] + " " + array[down] + "\"" + "\n"
// + "\"" + array[down] + " " + array[first] + "\"");
// qIndex++;
tmp = array[first];
array[first] = array[down];
array[down] = tmp;
out.println("{");
out.print("arraySwap on \"qarray\" position " + first + " with " + down);
out.println(" within 500 ms");
out.println("}");
}
out.println("{");
out.print("arraySwap on \"qarray\" position " + down + " with " + lastIndex);
out.println(" within 500 ms");
out.println("highlightArrayCell on \"qarray\" position " + down);
out.println("}");
return down;
}
