快速排序

void Quicksort(ElementType A[], int N) {
    Qsort(A, 0, N-1);
}

ElementType Median3(ElementType A[], int Left, int Right) {
    int Center = (Left + Right)/2;
    if (A[Left] > A[Center])
        swap(&A[Left], &A[Center]);
    if (A[Left] > A[Right])
        swap(&A[Left], &A[Right]);
    if (A[Center] > A[Right])
        swap(&A[Center], &A[Right]);
    swap(&a[Center], &A[Right-1]);
    return a[Right-1];
}

#define Cutoff (3)
void Qsort(Element A[], int Left, int Right) {
    int i,j;
    ElementType Pivot;
    if (Left+Cutoff <= Right) {
        Pivot = Median3(A, Left, Right);
        i=Left;
        j=Right-1;
        for (;;) {
            while (A[++i] < Pivot);
            while (A[--j] < Pivot);
            if (i<j)
                swap(&A[i], &A[j]);
            else
                break;
        }
        swap(&A[i], &A[Right-1]);
        Qsort(A, Left, i-1);
        Qsort(A, i+1, Right);
    }
    else {
        insertionsort(A+Left, Right-Left+1);
    }
}