C++实现计数排序

计数排序首先利用数组计数器count[]对每个数字在数组data[]中出现的次数进行计数.然后,计数器将所有<=i的整数的个数添加并存储到count[i]中.通过这种办法,count[i]-1表明i在data[]中的主位置.

时间复杂度: 4*max value
空间复杂度: O(n),需要额外计数器存储与额外最终排序空间存储,即不是在原有数组上进行排序.
算法稳定性: 稳定

补充强化C++基础,const int * 与 int * const
const int * 指针指向的数组,数组的指针可以移动(++,–等),但数组的值不能被改动.
int* const 指针指向的数组,数组的指针不可以移动(++,–等),但数组的值可以改动.

C++ 代码如下:
头文件:

    void countSort(unsigned const int* sortArray);

源文件:

template <typename T, unsigned int size>void Sort<T, size>::countSort(unsigned const int* sortArray){    unsigned int *tmpArray = new unsigned int[size];    memset(tmpArray, 0, size*sizeof(unsigned int));    unsigned int max = 0;    const unsigned int* startLoc = sortArray;    //First loop, find out the max value, the max value will define count array element num    for (unsigned int i = 0; i < size; i++)    {        loopTimes++;        moveTimes++;        unsigned int value = *sortArray;        if (value > max)        {            max = value;        }        tmpArray[i] = value;        if (i == size - 1)        {        }        else        {            sortArray++;        }    }    unsigned int* countArray = new unsigned int[max+1];    memset(countArray, 0, (max+1)*sizeof(unsigned int));    sortArray = startLoc;    //Second loop, count every elem frequency    for (unsigned int i = 0; i < size; i++)    {        loopTimes++;        moveTimes++;        unsigned int value = *sortArray;        countArray[value]++;        if (i == size - 1)        {        }        else        {            sortArray++;        }    }    unsigned int culValue = 0;    //Third loop, count the elem num less and equal than each elem    for (unsigned int i = 0; i < max + 1; i++)    {        loopTimes++;        moveTimes++;        culValue = culValue + countArray[i];        countArray[i] = culValue;    }    //Fourth loop, set the value into tmpArray    for (unsigned int i = 0; i < size; i++)    {        loopTimes++;        moveTimes++;        unsigned int sortArrayTailValue = *sortArray;        tmpArray[countArray[sortArrayTailValue] - 1] = sortArrayTailValue;        countArray[sortArrayTailValue]--;        sortArray--;    }    //print tmpArray, tmp Array is sorted list    for (unsigned int i = 0; i < size; i++)    {        if ((i != 0) && (i % 8 == 0))        {            cout << endl;        }        cout << tmpArray[i] << "  ";    }}