代码

随机产生数组

  public static int[] generateRandomArray(int maxSize, int maxValue) {
    // Math.random() --> [0,1) 所有小数，等概率返回1个
    // Math.random() * N --> [0,N) 所有小数，等概率返回1个
    // (int) (Math.random() * N) --> [0,N-1) 所有整数，等概率返回1个
    int[] arr = new int[(int) (Math.random() * maxSize)];
    for (int i = 0; i <arr.length; i++){
      arr[i] = (int) ((maxValue+1) * Math.random() - maxValue * Math.random())
    }
    return arr;
  }

复制 数组

  public static int[] copyArray(int[] arr){
    int[] arr2 = new int[arr.length];
    for (int i = 0; i < arr.length; i++){
      arr2[i] = arr[i];
    }
    return arr2;
  }

判断两数组是否相同

  public static boolean isEqual(int[] arr1, int[] arr2){
    for (int i = 0; i < arr1.length; i++){
      if(arr1[i] != arr2[i]){
        return false;
      }
    }
    return true;
  }

测试

  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);
      insertionSort(arr1);
      comparator(arr2);
      if (!isEqual(arr1, arr2)) {
        // 打印arr1
        // 打印arr2
        succeed = false;
        break;
      }
      System.out.println(succeed ? "Nice!" : "Fucking fucked");
    }
  }

  public static void insertionSort(int[] arr) {
    if (arr == null || arr.length < 2) {
      return;
    }

    for (int i = 1; i < arr.length; i++) {
      for (int j = i - 1; j >= 0 && arr[j] > arr[j + 1]; j--) {
        swap(arr, j, j + 1);
      }
    }
  }

  // for test
  public static void comparator(int[] arr) {
    Arrays.sort(arr);
  }