qsort.cpp

来自「This set of simulation files performs a 」· C++ 代码 · 共 31 行

void swap(register int *l, register int *r)
{
    register int temp = *r;
    *r = *l;
    *l = temp;
}

void qsort(float *arr, int *idx, int size)
{    
    register int pivotidx;
    register float pivotval;
    register int i;
    
    if (size <= 1) 
        return;
	pivotidx = 0;
	pivotval = arr[idx[0]];
    for (i = 1 ; i < size ; i++) {
        // every number > pivotval gets moved towards the front
        if (arr[idx[i]] > pivotval) {
            pivotidx++;
            swap(&(idx[i]), &(idx[pivotidx]));
        }
    }
    // move the pivot number to the pivot index
    swap(&idx[pivotidx], &idx[0]);

    qsort(arr, idx, pivotidx);
    qsort(arr, &idx[pivotidx+1], size-pivotidx-1);
}