Merge sort

MergeSort.java

/**
 *
 Merge sort O(n log(n)):
 - Break array in two parts and sort them recursively
 - Merge two sorted array in one resulting array

 */
public class MergeSort {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int[] array = new int[n];
        for (int i = 0; i < n; i++) {
            array[i] = scanner.nextInt();
        }
        array = getArraySorted(array, 0, array.length - 1);
        for (int i : array) {
            System.out.print(i + " ");
        }
    }

    private static int[] getArraySorted(int[] array, int start, int end) {
        int[] res = new int[end + 1 - start];
        int j = 0;
        for (int i = start; i <= end; i++) {
            res[j] = array[i];
            j++;
        }
        start = 0;
        end = res.length - 1;
        if (start == end) {
            return res;
        }
        int mid = (start + end) / 2;
        int[] sortedLeft = getArraySorted(res, start, mid);
        int[] sortedRight = getArraySorted(res, mid + 1, end);
        array = merge(res, sortedLeft, sortedRight, start, end);
        return array;
    }

    private static int[] merge(int[] array, int[] sortedLeft, int[] sortedRight, int start, int end) {
        int leftIndex = 0;
        int rightIndex = 0;

        for (int i = start; i <= end; i++) {
            if (leftIndex < sortedLeft.length && rightIndex < sortedRight.length) {
                if (sortedLeft[leftIndex] < sortedRight[rightIndex]) {
                    array[i] = sortedLeft[leftIndex];
                    leftIndex++;
                } else {
                    array[i] = sortedRight[rightIndex];
                    rightIndex++;
                }
            } else if (leftIndex < sortedLeft.length) {
                array[i] = sortedLeft[leftIndex];
                leftIndex++;
            } else if (rightIndex < sortedRight.length) {
                array[i] = sortedRight[rightIndex];
                rightIndex++;
            }
        }
        return array;
    }
}