面试：排序算法代码实现

• 冒泡排序
• 插入排序
• 希尔排序
• 选择排序
• 堆排序

冒泡排序

/*====================冒泡排序=======================*/
void bubble_sort(int nums[], int n)
{
    for (int i = 0; i < n; i++)
    {
        bool has_swapped = false;
        int j = n - 1;
        while (j - 1 >= i)
        {
            if (nums[j - 1] > nums[j])
            {
                swap(nums[j - 1], nums[j]);
                has_swapped = true;
            }
            j--;
        }
        if (!has_swapped)
            break;
    }
}

插入排序

/*==================插入排序=========================*/
void insert_sort(int nums[], int n)
{
    for (int i = 1; i < n; i++)
    {
        int temp = nums[i];
        int j = i;
        while (j - 1 >= 0)
        {
            if (nums[j - 1] > nums[j])
            {
                nums[j] = nums[j - 1];
                j--;
            }
            else
                break;
        }
        nums[j] = temp;
    }
}

希尔排序

/*======================希尔排序==================================*/
void shell_sort(int nums[], int n)
{
    for (int increment = n / 2; increment > 0; increment /= 2)
    {
        for (int i = increment; i < n; i++)
        {
            int temp = nums[i];
            int j = i;
            while (j - increment >= 0)
            {
                if (nums[j - increment] > nums[j])
                {
                    nums[j] = nums[j - increment];
                    j -= increment;
                }
                else
                    break;
            }
            nums[j] = temp;
        }
    }
}

选择排序

/*================选择排序=============================*/
int find_index_of_min(int nums[], int start, int end);
void select_sort(int nums[], int n)
{
    for (int i = 0; i < n; i++)
    {
        int indexOfMin = find_index_of_min(nums, i, n - 1);
        swap(nums[indexOfMin], nums[i]);
    }
}

堆排序

/*================堆排序==========================*/
void perc_down(int nums[], int index, int end)
{
    int temp = nums[index];
    int parent = index;
    while (2 * parent + 1 < end)
    {
        int next = 2 * parent + 1;
        if (next + 1 < end && nums[next + 1] > nums[next])
            next++;
        if (nums[next] > temp)
        {
            nums[parent] = nums[next];
            parent = next;
        }
        else
            break;
    }
    nums[parent] = temp;
}

void heap_sort(int nums[], int n)
{
    //在原数组上建立最大堆
    for (int i = (n - 1 - 1) / 2; i >= 0; i--)
    {
        perc_down(nums, i, n);
    }

    for (int i = n - 1; i >= 0; i--)
    {

        //依次从最大堆中取出最大元素放到原数组正确的位置上
        swap(nums[0], nums[i]);
        //调整最大堆
        perc_down(nums, 0, i);
    }
}