content: package class01;
  
  import java.util.Arrays;
  
  public class Code05_BubbleSort {
  
  	public static void bubbleSort(int[] arr) {
  		if (arr == null || arr.length < 2) {
  			return;
  		}
  		for (int end = arr.length - 1; end > 0; end--) {
  			for (int i = 0; i < end; i++) {
  				if (arr[i] > arr[i + 1]) {
  					swap(arr, i, i + 1);
  				}
  			}
  		}
  	}
  
  	// 交换arr的i和j位置上的值
  	public static void swap(int[] arr, int i, int j) {
  		int tmp = arr[i];
  		arr[i] = arr[j];
  		arr[j] = tmp;
  	}
  
  	// for test
  	public static void comparator(int[] arr) {
  		Arrays.sort(arr);
  	}
  
  	// for test
  	public static int[] generateRandomArray(int maxSize, int maxValue) {
  		int[] arr = new int[(int) ((maxSize + 1) * Math.random())];
  		for (int i = 0; i < arr.length; i++) {
  			arr[i] = (int) ((maxValue + 1) * Math.random()) - (int) (maxValue * Math.random());
  		}
  		return arr;
  	}
  
  	// for test
  	public static int[] copyArray(int[] arr) {
  		if (arr == null) {
  			return null;
  		}
  		int[] res = new int[arr.length];
  		for (int i = 0; i < arr.length; i++) {
  			res[i] = arr[i];
  		}
  		return res;
  	}
  
  	// for test
  	public static boolean isEqual(int[] arr1, int[] arr2) {
  		if ((arr1 == null && arr2 != null) || (arr1 != null && arr2 == null)) {
  			return false;
  		}
  		if (arr1 == null && arr2 == null) {
  			return true;
  		}
  		if (arr1.length != arr2.length) {
  			return false;
  		}
  		for (int i = 0; i < arr1.length; i++) {
  			if (arr1[i] != arr2[i]) {
  				return false;
  			}
  		}
  		return true;
  	}
  
  	// for test
  	public static void printArray(int[] arr) {
  		if (arr == null) {
  			return;
  		}
  		for (int i = 0; i < arr.length; i++) {
  			System.out.print(arr[i] + " ");
  		}
  		System.out.println();
  	}
  
  	// for test
  	public static void main(String[] args) {
  		int testTime = 500000;
  		int maxSize = 100;
  		int maxValue = 100;
  		boolean succeed = true;
  		for (int i = 0; i < testTime; i++) {
  			int[] arr1 = generateRandomArray(maxSize, maxValue);
  			int[] arr2 = copyArray(arr1);
  			bubbleSort(arr1);
  			comparator(arr2);
  			if (!isEqual(arr1, arr2)) {
  				succeed = false;
  				break;
  			}
  		}
  		System.out.println(succeed ? "Nice!" : "Fucking fucked!");
  
  		int[] arr = generateRandomArray(maxSize, maxValue);
  		printArray(arr);
  		bubbleSort(arr);
  		printArray(arr);
  	}
  
  }
  