C++版常用算法之排序整理

 

排序算法中用到的函数：

void Swap(int* a, int* b)
{
    int tmp = *a;
    *a = *b;
    *b = tmp;
}

void PrintArray(int data[],int length)
{
    for (int i = 0; i < length; i++)
    {
        cout << data[i] << " ";
    }
    cout << endl;
}

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1.冒泡排序

/*交换排序：冒泡排序*/
void bubbleSort(int data[], int length)
{
    if (data == nullptr || length <= 0)
        return;
    for (int i = 0; i < length - 1; i++)
    {
        for (int j = 0; j < length - i - 1; j++)
        {
            if (data[j]>data[j + 1])
                Swap(&data[j], &data[j + 1]);
        }
    }
}

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2.快速排序

/*交换排序：快速排序*/

int Partition(int data[], int length, int start, int end)
{
    if (data == nullptr || length <= 0 || start < 0 || end >= length)
        throw new exception("invalid parameters!");

    int index = start;
    int small = start - 1;
    for (index; index < end; index++)
    {
        if (data[index] < data[end])
        {
            ++small;
            if (small != index)
            {
                Swap(&data[small], &data[index]);
            }
        }
    }

    ++small;
    Swap(&data[small], &data[end]);

    return small;
}

void QuickSort(int data[], int length, int start, int end)
{
    if (start == end)
        return;

    int index = Partition(data, length, start, end);
    if (index > start)
        QuickSort(data, length, start, index - 1);
    if (index < end)
        QuickSort(data, length, index + 1, end);
}

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3.堆排序

/*选择排序：堆排序*/
void HeapAdjust(int data[], int s, int length)
{
    int tmp = data[s];
    int child = s * 2 + 1; //这是当前节点的左孩子！！！
    while (child < length)
    {
        if (child + 1 < length&&data[child] < data[child + 1])
            ++child;  //要找到左右孩子中比较大的那个
        if (data[s] < data[child])
        {
            data[s] = data[child];
            s = child;
            child = s * 2 + 1;
        }
        else
            break;
        data[s] = tmp;
    }
}

void BuildHeap(int data[], int length)
{
    if (data == nullptr || length <= 0)
        return;
    for (int i = (length - 1) / 2; i >= 0; i--)  //初始建堆是从下往上
    {
        HeapAdjust(data, i, length);
    }
}

void HeapSort(int data[], int length)
{
    BuildHeap(data, length);
    for (int i = length - 1; i > 0; --i)
    {
        Swap(&data[0], &data[i]);
        HeapAdjust(data, 0, i);
    }
}

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4.简单选择排序

/*选择排序：简单选择排序*/
void SelectSort(int data[], int length)
{
    if (data == nullptr || length <= 0)
        return;
    for (int i = 0; i < length - 1; i++)
    {
        int min = i;
        for (int j = i+1; j < length; j++)
        {   
            if (data[min]>data[j])
            {
                min = j;
            }
        }
        Swap(&data[min], &data[i]);
    }
}

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5.直接插入排序

/*插入排序：直接插入排序*/
void InsertSort(int data[], int length)
{
    for (int i = 1; i < length; i++)
    {
        if (data[i] < data[i - 1])
        {
            int tmp = data[i];
            int j = i-1;
            while (j >= 0 && data[j]>tmp)
            {
                data[j+1] = data[j];
                j -= 1;
            }
            data[j + 1] = tmp;
        }
    }
}

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6.希尔排序

/*插入排序：希尔排序*/
void ShellSort(int data[], int length)
{
    int i, j, gap;
    for (gap = length / 2; gap > 0; gap /= 2)
    {
        for (i = 0; i < gap; i++)
        {
            //直接插入排序
            for (j = i + gap; j < length; j += gap)
            {
                if (data[j] < data[j - gap])
                {
                    int tmp = data[j];
                    int k = j - gap;
                    while (k >= 0 && data[k]>tmp)
                    {
                        data[k + gap] = data[k];
                        k -= gap;
                    }
                    data[k + gap] = tmp;
                }
            }
        }
    }
}

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7.归并排序

/*归并排序*/
void MergeArray(int data[], int start, int mid, int end)
{
    vector<int> tmp;
    int another_start = mid + 1;
    int i = start;
    int j = another_start;
    while (i <= mid&&j <= end)
    {
        if (data[i] < data[j])
        {
            tmp.push_back(data[i++]);
        }
        else
        {
            tmp.push_back(data[j++]);
        }
    }
    while (i <= mid)
    {
        tmp.push_back(data[i++]);
    }
    while (j <= end)
    {
        tmp.push_back(data[j++]);
    }

    for (unsigned int i = 0; i < tmp.size(); i++)
    {
        data[start + i] = tmp[i];
    }


}
void MergeSort(int data[], int start, int end)
{
    if (data == nullptr || start < 0)
        throw new exception("invalid parameters!");
    if (start < end)
    {
        int mid = (start + end) / 2;
        MergeSort(data, start, mid);
        MergeSort(data, mid + 1, end);
        MergeArray(data, start, mid, end);
    }
}

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测试

#include <iostream>
#include <stdlib.h>
#include <vector>

using namespace std;

int main()
{
    //int data[] = { 49, 38, 65, 97, 76, 13, 27, 49 };
    int data[] = { 0, 9, 8, 7, 6, 5, 4, 3, 2, 1 };
    int length = sizeof(data) / sizeof(data[0]);

    bubbleSort(data, length);
    PrintArray(data,length);

    QuickSort(data, length, 0, length - 1);
    PrintArray(data, length);

    HeapSort(data, length);
    PrintArray(data, length);

    SelectSort(data, length);
    PrintArray(data, length);

    InsertSort(data, length);
    PrintArray(data, length);

    ShellSort(data, length);
    PrintArray(data, length);

    MergeSort(data, 0, length - 1);
    PrintArray(data,length);

    system("pause");
    return 0;
}

感谢博主分享：https://blog.csdn.net/sweetcandy2/article/details/72903235