java归并排序

import java.util.Random;

public class testmergesort {
	public static void main(String[] args) {
		int ary[] = getArray(100);
		show(ary, "ary");
		show(sort(ary, 1), "result");

	}
	private static int[] sort(int[] ary, int step) {
		int j = 0;//
		int k = 0;//
		int copyary[] = new int[ary.length];
		for (int a = 0; a < ary.length; a++) {
			copyary[a] = ary[a];

		}
		int start = 0;
		for (int i = 0; i < ary.length; i++) {
			if (k == step && j == step) {
				start = i;
				k = 0;
				j = 0;
			}
			if (j == step) {
				ary[i] = copyary[start + k + step];
				k++;
				continue;
			}
			if (k == step) {
				ary[i] = copyary[start + j];
				j++;
				continue;
			}
			if (start + k + step >= ary.length) {
				ary[i] = copyary[start + j];
				j++;
				continue;
			}
			if (copyary[start + j] < copyary[start + k + step]) {
				ary[i] = copyary[start + j];
				j++;

			} else {
				ary[i] = copyary[start + k + step];
				k++;
			}

		}
		if (step <= ary.length / 2){
			step = step * 2;
			ary = sort(ary, step);
		}
		return ary;
	}

	private static void show(int ary[], String name) {
		System.out.print(name + ":{");
		for (int i = 0; i < ary.length; i++) {
			System.out.print(ary[i] + ",");
		}
		System.out.println("}");
	}

	public static int[] getArray(int length) {
		int[] result = new int[length];
		Random random = new Random();
		for (int i = 0; i < length; i++) {
			result[i] = random.nextInt(100);
		}
		return result;
	}
}