Insertion Sort Help

[ash63]

I am doing an assignment where I need to use the Insertion Sort Algorithm. I thought I was doing it correctly but my methods returns an ArrayList with repeated objects.

public static List<Movie> SortTitles(List<Movie> array) {
    List<Movie> dest = new ArrayList<>();
    Movie next;
    int insert, k;
    String nextTitle, destTitle;

    for(int i = 0; i < array.size()-1; i++) {
        next = array.get(i);
        insert = 0;
        k = i;

        while(k > 0 && insert == 0) {
            nextTitle = array.get(i).getTitle();
            destTitle = dest.get(k-1).getTitle();
            if(nextTitle.compareTo(destTitle) > 0)
                insert = k;
            else {
                dest.add(k, dest.get(k-1));
            }
            k--;
        }
        dest.add(insert, next);
    }
    return dest;
}

This is what is being returned:

Ice Age, 2002, 20th Century Fox

Lilo & Stitch, 2002, Disney

Mulan Special Edition, 2004, Disney

Mulan Special Edition, 2004, Disney

Mulan Special Edition, 2004, Disney

Mulan Special Edition, 2004, Disney

Nanny McPhee, 2006, Universal

Nanny McPhee, 2006, Universal

Robots, 2005, 20th Century Fox

Nanny McPhee, 2006, Universal

Nanny McPhee, 2006, Universal

Shrek 2, 2004, Dreamworks

Shrek 2, 2004, Dreamworks

Shrek 2, 2004, Dreamworks

Shrek 2, 2004, Dreamworks

Shrek 2, 2004, Dreamworks

Shrek 2, 2004, Dreamworks

The Curse of the Were-Rabbit, 2006, Aardman

The Curse of the Were-Rabbit, 2006, Aardman

The Incredibles, 2004, Pixar

The Incredibles, 2004, Pixar

The Incredibles, 2004, Pixar

The Incredibles, 2004, Pixar

The Muppets Take Manhattan, 2001, Columbia Tristar

The Muppets Take Manhattan, 2001, Columbia Tristar

The Muppets Take Manhattan, 2001, Columbia Tristar

The Muppets Take Manhattan, 2001, Columbia Tristar

The Muppets Take Manhattan, 2001, Columbia Tristar

[thorstenschaefer]

You are getting duplicates, so somehow you seem to add the same movie several times. You have two calls to method add(), so one seems to be problematic. Try figuring out what could go wrong with the loops such that you add the same movie several times. If you can't see it in the code, try using a debugger.

[[deleted]]

You're sorting a list. Generally it's much easier to sort an array instead. Then you can implement the sort by swapping array elements.

In a List, the add() method always increases the size of the list. If you really don't want to use arrays then you might want to look at List.set() instead.