用尽可能少的测试用例分别对希尔排序实实现语句覆盖、分支覆盖、条件覆盖

对于希尔排序的实现，我们可以参考以下的C++代码：

void shellSort(int arr[], int n) 
{ 
    // Start with a big gap, then reduce the gap 
    for (int gap = n/2; gap > 0; gap /= 2) 
    { 
        // Do a gapped insertion sort for this gap size. 
        // The first gap elements a[0..gap-1] are already in gapped order 
        // keep adding one more element until the entire array is gap sorted 
        for (int i = gap; i < n; i += 1) 
        { 
            // add a[i] to the elements that have been gap sorted 
            // save a[i] in temp and make a hole at position i 
            int temp = arr[i]; 
  
            // shift earlier gap-sorted elements up until the correct location for a[i] is found 
            int j;             
            for (j = i; j >= gap && arr[j - gap] > temp; j -= gap) 
                arr[j] = arr[j - gap]; 
              
            // put temp (the original a[i]) in its correct location 
            arr[j] = temp; 
        } 
    } 
} 

实现语句覆盖的测试用例：

// 测试用例1：空数组
int arr1[] = {};
shellSort(arr1, 0);

// 测试用例2：数组长度为1
int arr2[] = {1};
shellSort(arr2, 1);

// 测试用例3：数组长度为偶数
int arr3[] = {3, 5, 2, 8};
shellSort(arr3, 4);

// 测试用例4：数组长度为奇数
int arr4[] = {7, 1, 6, 2, 8};
shellSort(arr4, 5);

分支覆盖的测试用例：

// 测试用例1：数组长度为偶数
int arr1[] = {3, 5, 2, 8};
shellSort(arr1, 4);

// 测试用例2：数组长度为奇数
int arr2[] = {7, 1, 6, 2, 8};
shellSort(arr2, 5);

条件覆盖的测试用例：

// 测试用例1：数组长度为偶数
int arr1[] = {3, 5, 2, 8};
shellSort(arr1, 4);

// 测试用例2：数组长度为奇数
int arr2[] = {7, 1, 6, 2, 8};
shellSort(arr2, 5);

// 测试用例3：数组长度为3
int arr3[] = {9, 4, 2};
shellSort(arr3, 3);