希尔排序

package demo;

public class ShellSort {
	public static void main(String[] args) {
		int[] arr = {5,4,3,2,1,0};
		printArr(arr);
		shellSort(arr);
		printArr(arr);
	}

	private static void shellSort(int[] arr) {
		int gap = arr.length / 2;
		while (gap > 0) {
			for (int i = gap; i < arr.length; i++) {
				int tmp = arr[i];
				int j = i - gap;
				for (; j >= 0 && arr[j] > tmp; j = j - gap) {
					arr[j+gap]=arr[j];	
				}
				arr[j+gap] = tmp;
				
			}
			gap = gap/2;
		}
	}
	/**
	 * 打印数组；
	 * 
	 * @param arr
	 */
	private static void printArr(int[] arr) {
		if (arr == null) {
			return;
		}
		for (int i = 0; i < arr.length; i++) {
			if (i != arr.length - 1) {
				System.out.print(arr[i] + " ");
			} else {
				System.out.print(arr[i]);
			}
		}
		System.out.println();
	}
}