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Message:
Something I didn't understand:
Posted by Eduardo on November 08, 2001 at 2:23 PM
Wow, Brian! Thank you very much! Yeah, I do have duplicity in my list. I was sorting using the Collections.sort( ---, ---, LongComparator), but looks like something else was stucking the linked list. Probably the duplicity. I added 2 questions I still have in your code: >
>
> import java.util.*;> public class List
> {
> //using actual Long values (rather than Strings) for simplicity
> public static Object[][] DATA = {
> { "FirstItem", new Long(50) },
> { "SecondItem", new Long(10) },
> { "ThirdItem", new Long(80) },
> { "FourthItem", new Long(0) },
> { "FifthItem", new Long(10) }
> }; 1. How do I input my data, from the LinkedList, inside this Object? I've tried this way, but doesn't accept (I've declared the object as public static Object[][] DATA;: ListIterator d = EventList.listIterator();
ListIterator f = TimeList.listIterator();
while ( d.hasNext() == true)
{
DATA [d.next()][f.next()];
} > /**
> * Sorts the two lists. Preserves the relative order of two events happening at the same time.
> */
> public static void main(String[] args)
> {
> //initializing the two linked list off of the data in the constant array
> LinkedList names = new LinkedList();
> LinkedList times = new LinkedList(); > for (int i=0; i < DATA.length; i++)
> {
> names.add(DATA[i][0]);
> times.add(DATA[i][1]);
> } 2. Up here I didn't understand very well. I know the code works, but I just would like to understand it better. You add to names the Object DATA [i][0]... and to times the Object DATA [i][1]. But [i][0] isn't taking only the first Long object you have in the list and changing only the names? And the same happening for the [i][1], where it takes the second Long?
> //clone the array, and sort
> LinkedList sortedTimes = (LinkedList) times.clone();
> Collections.sort(sortedTimes);
> //for each time in the sorted times list, find it's index in the unsorted times list.
> //this can be used to find the corresponding element in the names list.
> LinkedList sortedNames = new LinkedList(); > //As we find an index for each time, replace it with a token object to indicate that it's already been used;
> //this will allow for duplicate times. We clone the list b/c we assume preserving the original list is
> //important.
> Object BLANK = new Object();
> LinkedList unsortedTimes = (LinkedList) times.clone();
> for (Iterator i = sortedTimes.listIterator(); i.hasNext(); )
> {
> Long time = (Long) i.next();
> int index = 0;
> while (unsortedTimes.get(index) != time || unsortedTimes.get(index) == BLANK)
> index++;
> unsortedTimes.set(index, BLANK);
> sortedNames.add(names.get(index));
> } > //showing our results:
> for (int i=0; i < sortedNames.size(); i++)
> {
> System.out.println(sortedNames.get(i) + ":" + sortedTimes.get(i));
> }
> }
> }
>
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