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Thread: Help with Sorting Algorithm
 09202017, 08:11 PM #1Member
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Help with Sorting Algorithm
I have been trying to get this program to work for sometime now and I am struggling. I am trying to call the InsertionSort method inside of the shell sort, to sort a random list of N numbers. I am also trying to make a counter for how many times it goes through the list to process, that is why I have count = count + insertionSort in there. I know that the InsertionSort code works, but I am getting the following error when I run it.
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 3
at MyClass.ShellSort(MyClass.java:64)
at MyClass.main(MyClass.java:18)
Here is my code for it so far:
Java Code:import java.util.Random; public class MyClass { public static void main(String args[]) { Random rn = new Random(); int N = 16; int list[] = new int[N+1]; for (int i = 1; i <= N; ++i) { //  random list list[i] = rn.nextInt(100); } System.out.println("unsorted"); for (int i = 1; i <= N; ++i) { System.out.println(list[i]); } int shellsort = ShellSort(list, N); System.out.println(N + " > " + shellsort); System.out.println("sorted"); for (int i = 1; i <= N; ++i) { System.out.println(list[i]); } } public static int ShellSort(int list[], int N) { int count = 0; int passes = log2(N); while (passes >= 1) { int increment = (int) Math.pow(2, passes  1); int start = 1; int size = N / increment; int sublist[] = new int[N / increment + 1]; for (int i = start; i <= N; i += increment) { int j = 1; for (i = start; i <= N; i += increment) { sublist[j] = list[i]; ++j; } InsertionSort(sublist, N / increment); list[i] = sublist[j]; int insertionSort = InsertionSort(list, N); count = count + insertionSort; } passes = passes  1; } return count; } public static int InsertionSort(int list[], int N) { int counter = 0; for (int i = 2; i <= N; ++i) { int newElement = list[i]; int location = i  1; while ((location >= 1) && (list[location] > newElement)) { ++counter; list[location + 1] = list[location]; location = location  1; } ++counter; list[location + 1] = newElement; } return counter; } public static int log2(int x) { return (int)(Math.log(x) / Math.log(2)); } }
 09202017, 09:10 PM #2
Re: Help with Sorting Algorithm
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 3
at MyClass.ShellSort(MyClass.java:64)
Remember valid array indexes range from 0 to the array's length 1If you don't understand my response, don't ignore it, ask a question.
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