快排

private static void quicksort(String[] a, int lo0, int hi0) {
        int lo = lo0;
        int hi = hi0;

        if (lo >= hi)
            return;

        String mid = a[(lo + hi) / 2];
        while (lo < hi) {
            while (lo<hi && a[lo].compareTo(mid) < 0)
                lo++;
            while (lo<hi && a[hi].compareTo(mid) > 0)
                hi--;
            if (lo < hi) {
                String T = a[lo];
                a[lo] = a[hi];
                a[hi] = T;
                lo++;
                hi--;
            }
        }
        if (hi < lo) {
            int T = hi;
            hi = lo;
            lo = T;
        }
        quicksort(a, lo0, lo);
        quicksort(a, lo == lo0 ? lo+1 : lo, hi0);
    }