冒泡排序(BubbleSort)

void BubbleSort(int arr[], int len)
{
    if (arr == NULL || len == 0) return;
    for (int i = 0; i < len - 1; i++)
    {
        for (int j = 0; j < len - i - 1; j++)
        {
            if (arr[j] > arr[j + 1])
            {
                arr[j] = arr[j] ^ arr[j + 1];
                arr[j + 1] = arr[j] ^ arr[j + 1];
                arr[j] = arr[j] ^ arr[j + 1];
            }
        }
    }
}

选择排序（SelectSort）

遍历一遍数据，找到最小值或最大值放入相应位置上

• 设a[0]为最小值，遍历数组，与最小值比较，找到数组最小值，记录下标，与数组a[0]元素交换，重复过程

代码

void SeclectSort(int arr[],int n)
{
    int MinIndex=0;
    int k = 0;
    if (arr == NULL || n <= 0)
        return;
    for (int i = 0; i < n; i++)
    {
        MinIndex = i;
        for (int j = i + 1; j < n; j++)
        {
            if (arr[j] < arr[MinIndex])
                MinIndex = j;
        }
        swap(arr[i], arr[MinIndex]);
    }
}

插入排序（InsertSort)

将待排序的数据分成两部分，一部分有序，一部分无序，将无序的元素依次插入到有序中

代码

void InsertSort(int arr[], int n)
{
    if (arr == NULL || n == 0) return;
    int i, j, temp;
    for (int i = 1; i < n; i++)
    {
        temp = arr[i];
        j = i - 1;
        while (temp < arr[j] && j >= 0)
        {
            arr[j + 1] = arr[j];
            j--;
        }
        arr[j + 1] = temp;
    }
}

快速排序（QuickSort）

找一个标准值，比标准值小的放到其左侧，大的放在右侧，左右两半部分分别重复以上操作

int Sort(int arr[], int low, int high)
{
    if (arr == NULL || sizeof(arr)/sizeof(*arr)==0 ) return;
    int pivot = arr[low];
    while (low < high)
    {
        while (low<high && arr[high]>=pivot)
        {
            high--;
        }
        arr[low] = arr[high];
        while (low < high && arr[low] <= pivot)
        {
            low++;
        }
        arr[high] = arr[low];
    }
    arr[low] = pivot;
    return low;
}
​
void QuickSort(int arr[], int low,int high)
{
    if (low < high)
    {
        int pivot = Sort(arr, low, high);
        QuickSort(arr, low, pivot - 1);
        QuickSort(arr, pivot+1, high);
    }
}

堆排序（HeapSort）

大堆：父亲的值比孩子大

小堆：父亲的值比孩子小

​

 

void MaxHeapfy(int arr[],int dad, int len)
{
    int son = 2 * dad + 1;
    if (arr == NULL || len == 0) return;
    while (son < len)
    {
        if (son + 1 < len && arr[son + 1] > arr[son]) son++;
        if (arr[dad] > arr[son]) return;
        else
        {
            swap(arr[son], arr[dad]);
            dad = son;
            son = 2 * dad + 1;
        }
    }
}
​
void HeapSort(int arr[], int len)
{
    for (int i = len / 2 - 1; i >= 0; i--)
    {
        MaxHeapfy(arr, i, len);
    }
    for (int i = len - 1; i > 0; i--)
    {
        swap(arr[0], arr[i]);
        len--;
        MaxHeapfy(arr,0 ,i);
    }
}

希尔排序（ShellSort）

数据分组，各组内插入排序

void ShellSort(int arr[], int len)
{
    if (arr == NULL || len == 0) return;
    for (int gap = len / 2; gap > 0; gap /= 2)
    {
        for (int i = gap; i < len; i++)
        {
            int temp = arr[i];
            int j = i - gap;
            while (j >= 0 && temp < arr[j])
            {
                arr[j + gap] = arr[j];
                j = j - gap;
            }
            arr[j + gap] = temp;
        }
    }
}

归并排序(MergeSort)

将多个有序数组进行合并

void Merge(int arr[], int l,int r)
{
    int mid = l + (r - l) / 2;
    int p0 = 0;
    int p1 = l;
    int p2 = mid + 1;
    int* aux = new int[r-l+1];
    while (p1 <= mid && p2 <= r)
    {
        if (arr[p1] < arr[p2])
            aux[p0++] = arr[p1++];
        else
            aux[p0++] = arr[p2++];
    }
    while (p1 <= mid)
        aux[p0++] = arr[p1++];
    while (p2 <= r)
        aux[p0++] = arr[p2++];
    for (int i = 0; i < p0; i++)
        arr[i + l] = aux[i];
    delete[] aux;
}
​
void MergeSort(int arr[], int l, int r)
{
    if (arr == NULL || l >= r) return;
    int mid = l + (r - l) / 2;
    MergeSort(arr, l, mid);
    MergeSort(arr, mid + 1, r);
    Merge(arr, l,r);
}

基数排序(RadixSort)

不基于比较的排序

只能用于非负数排序

LSD ：低位优先

MSD：高位优先

int GetMax(int arr[], int len)
{
    int Maxval = *max_element(arr, arr + len);
    int Maxbit = 0;
    while (Maxval>0)
    {
        Maxval /= 10;
        Maxbit++;
    }
    return Maxbit;
}
​
void RadixSort(int arr[], int len)
{
    int n = GetMax(arr, len);
    int* count = new int[10];
    int* temp = new int[len];
    int radix = 1;
    for (int i = 0; i < n; i++)
    {
        for (int i = 0; i < 10; i++)
            count[i] = 0;
        for (int i = 0; i < len; i++)
        {
            count[(arr[i] / radix) % 10]++;
        }
        for (int i = 1; i < 10; i++)
        {
            count[i] += count[i - 1];
        }
        for (int i = len - 1; i >= 0; i--)
        {
            temp[count[(arr[i] / radix) % 10] - 1] = arr[i];
            count[(arr[i] / radix) % 10]--;
        }
        for (int i = 0; i < len; i++)
        {
            arr[i] = temp[i];
        }   
        radix *= 10;
    }
    delete[] count;
    delete[] temp;
}

桶排序（BucketSort)

void BucketSort(int arr[], int len)
{
    int Maxval = *max_element(arr, arr + len);
    int Minval = *min_element(arr, arr + len);
    int bucket = len;
    int gap = (Maxval - Minval) / (bucket - 1);
    vector<int>* aux = new vector<int>;
    vector<list<int>> vec ;
    vector<int>* sorted = new vector<int>;
    vec.resize(bucket);
    for (int i = 0; i < len; i++)
    {
        int index = (arr[i] - Minval) / gap;
        vec.at(index).push_back(arr[i]);
    }
    for (int i=0;i<vec.size();i++)
    {
        aux->assign(vec[i].begin(), vec[i].end());
        sort(aux->begin(), aux->end());
        sorted->insert(sorted->end(), aux -> begin(), aux->end());
    }
    for (int i = 0; i < len; i++)
        arr[i] = sorted->at(i);
    delete aux;
    delete sorted;
​
}

排序比较