CODEWITHSUNDEEP
java
Pope_penguin
Pope_penguin

Reputation: 1

Insertion sort in descending order (java)?

So I'm trying to make an insertion sort program sort numbers in descending order. However, I'm not entirely sure what to do with this specific program. 

    public static void insertionSort(int[] arr)
{
    System.out.println(Arrays.toString(arr));

    for (int i = 1; i < arr.length; i++)
    {
        int curNumber = arr[i];
        int curIndex = i+1;
        while ( curIndex <= 0 && arr[curIndex] < curNumber)
        {
            arr[curIndex+1] = arr[curIndex];
            curIndex--;
        }
        arr[curIndex - 1] = curNumber;
        System.out.println(Arrays.toString(arr));
    }

}

I've tried changing the < to a > on line 9 (while (curIndex <= 0 && arr[curIndex] < curNumber)), under the logic that the greater number will be moved, but it produces entirely wrong values for the sort. What should I do?

Upvotes: 0

Views: 182

Answers (1)

Bahij.Mik
Bahij.Mik

Reputation: 1484

You should check if currentIndex is >= 0, also the current index starts at i - 1

public static void insertionSort(int[] arr)
{
    System.out.println(Arrays.toString(arr));

    for (int i = 1; i < arr.length; i++)
    {
        int curNumber = arr[i];
        int curIndex = i - 1;
        while ( curIndex >= 0 && arr[curIndex] < curNumber)
        {
            arr[curIndex+1] = arr[curIndex];
            curIndex--;
        }
        arr[curIndex + 1] = curNumber;
        System.out.println(Arrays.toString(arr));
    }

}

Upvotes: 1

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