排序算法04-快速排序（用C++、C#、lua实现）

目录

• 1、快速排序
• 2、C#实现
• 3、C++实现
• 4、lua实现

本文为排序算法-快速排序的代码实现。
作者水平比较差，有错误的地方请见谅。

1、快速排序

冒泡排序属于交换排序。

平均时间复杂度：O(n*logn)
空间复杂度：
最坏：O(logn)
最好：O(n)

2、C#实现

QuickSort.cs

	public static class QuickSort
    {
        public static void Quick(int[] numbers)
        {
            if (numbers == null || numbers.Length < 2)
            {
                Console.WriteLine("参数数组有误");
                return;
            }

            QSort(numbers, 0, numbers.Length-1);
        }
        public static void QSort(int[] numbers,int low,int high)
        {
            if (low < high)
            {
                int index = Partition(numbers, low, high);
                //对左右子表进行递归排序
                QSort(numbers, low, index - 1);
                QSort(numbers, index + 1, high);
            }
        }

        public static int Partition(int[] numbers, int low, int high)
        {
            int temp = numbers[low];
            while (low < high)
            {
                //比temp小的移动到左边
                while (low < high && numbers[high] >= temp)
                {
                    high--;
                }
                numbers[low] = numbers[high];
                //比temp大的移动到右边
                while (low < high && numbers[low] <= temp)
                {
                    low++;
                }
                numbers[high] = numbers[low];
            }
            numbers[low] = temp;
            return low;
        }
    }

Program.cs

class Program
    {
        static void Main(string[] args)
        {
            int[] numbers = { 49, 38, 65, 97, 76, 13, 27, 49 };
            QuickSort.Quick(numbers);

            for (int i = 0; i < numbers.Length; i++)
            {
                Console.Write(numbers[i] + " ");
            }
            Console.WriteLine();

            Console.ReadKey();
        }
    }

3、C++实现

.cpp

///直接插入排序
class QuickSort
{
public:
    static void Quick(int numbers[],int low,int high);
    static void QSort(int numbers[],int low,int high);
    static int Partition(int numbers[],int low,int high);
};

void QuickSort::Quick(int numbers[],int low,int high)
{
    if (numbers == NULL || (high+1) < 2)
    {
        cout<<"参数数组有误"<<endl;
        return;
    }
    QSort(numbers,low,high);
}
void QuickSort::QSort(int numbers[],int low,int high)
{
    if(low < high){
        int index = Partition(numbers,low,high);
        QSort(numbers,low,index-1);
        QSort(numbers,index+1,high);
    }
}
int QuickSort::Partition(int numbers[],int low,int high)
{
    int temp = numbers[low];
    while(low < high){
        while(low < high && numbers[high]>=temp){
            high--;
        }
        numbers[low] = numbers[high];
        while(low < high && numbers[low]<=temp){
            low++;
        }
        numbers[high] = numbers[low];
    }
    numbers[low] = temp;

    return low;
}

main.cpp

int main()
{
    int numbers[] = {49,38,65,97,76,13,27,49};
    int length = sizeof(numbers)/sizeof(numbers[0]);

    QuickSort::Quick(numbers,0,length - 1);

    for(int i=0;i<length;i++){
        cout<<numbers[i]<<" ";
    }
    cout<<endl;


    return 0;
}

4、lua实现

numbers = {49,38,65,97,76,13,27,49}
length = #numbers


function QuickSort(nums,low,high)
	if(low < high) then
		local index = Partition(nums,low,high)
		QuickSort(nums,low,index - 1)
		QuickSort(nums,index + 1,high)
	end
end


function Partition(nums,low,high)
	local temp = nums[low]
	while(low < high) do
		while(low < high and nums[high] >= temp) do
			high = high - 1
		end
		nums[low] = nums[high]
		while(low < high and nums[low] <= temp) do
			low = low + 1
		end
		nums[high] = nums[low]
	end

	nums[low] = temp
	return low
end

QuickSort(numbers,1,length)

for i=1,length,1 do
	io.write(numbers[i] .. ' ')
end
print()