Sorting - JAVA implementation [9] Hill sorting

package org.lion.euler.study.sort;

/**
 * Hill sort
 * <pre>
 * Principle: Insertion sort across interval elements, starting at 1/2 the length of the array until the interval is 1.
 * </pre>
 * @author lion
 *
 */
public class ShellSort extends AbstractSort {

	@Override
	public void sort(Integer[] array) {
		int inc = array.length / 2;
		while (inc > 0) {
			for (int i = 0, j = i; i < array.length - inc; i += 1, j = i) {
				int ai = array[i + inc];
				while (j >= 0 && ai < array[j]) {
					array[j + inc] = array[j];
					if (j - inc < 0) {
						j -= inc;
						break;
					}
					j -= inc;
				}
				array[j + inc] = ai;
			}

			inc /= 2;
		}
	}

}