不知道哪里出了问题，先记录一下，调试好了再提交
public class QuickSort {

public int swap(int a,int b) {
    int tmp = a;
    a = b;
    b = tmp;
    return a;
}

public int[] quickSort(int[] d, int first, int last) {
    int lower = first + 1;
    int upper = last;
    swap(d[first],d[(first+last)/2]);
    int bound = d[first];
    while (lower <= upper) {
        while (d[lower] < bound) {
            lower++;
        }
        while (bound < d[upper]) {
            upper--;
        }
        if (lower < upper) {
            swap(d[lower++],d[upper--]);
        } else {
            lower++;
        }
        swap (d[upper],d[first]);
        if (first < upper-1) {
            quickSort(d,first,upper-1);
        }
        if (upper+1 < last) {
            quickSort(d,upper + 1, last);
        }
    }
    return d;
}

}