各种排序算法小结

快速排序

#include <exception>
#include <time.h>
#include <cstdio>
#include <cstdlib>

int RandomInRange(int start, int end) {    
    srand((int)time(NULL));
    return start + rand() % (end - start + 1);
}

void Swap(int* x, int* y) {
    int t;
    t = *x;
    *x = *y;
    *y = t;
}

int Partition(int data[], int length, int start, int end) {
    if (data == NULL || length < 0 || start < 0 || end >= length)
        throw new std::exception("Invalid Parameters");

    int index = RandomInRange(start, end);
    Swap(&data[index], &data[end]);

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

    ++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);
}

void OutputList(int data[], int length)
{
    for (int i = 0; i<length-1; ++i)
    {
        printf("%d ", data[i]);
    }
    printf("
");
}

int main() {
    int data[9] = { 1,3,7,2,9,6,8,5 };

    OutputList(data, 9);

    QuickSort(data, 9, 0, 7);

    OutputList(data, 9);

    system("pause");
    return 0;
}