Java Quicksort Profile

class SortTest{
    private static void quicksort(int[] list, int low, int high){
        int pivot = list[low + (high-low)/2];
        int i = low;
        int j = high;
        while (i <= j) {
            while (list[i] < pivot) {
                i++;
            }
            while (list[j] > pivot) {
                j--;
            }
            if (i <= j) {
                int temp = list[i];
                list[i] = list[j];
                list[j] = temp;
                i++;
                j--;
            }
        }
        if (low < j){
            quicksort(list, low, j);
        }
        if (i < high){
            quicksort(list, i, high);
        }
    }

    public static long testSorted(int size){
        // create array
        int[] sorted = new int[size];
        for(int i=0; i<size; i++){
            sorted[i] = i;
        }
        // sort it
        long tstart = System.nanoTime();
        quicksort(sorted, 0, size-1);
        return System.nanoTime() - tstart;
    }

    public static long testRandom(int size){
        // create array
        int[] permuted = new int[size];
        for(int i=0; i<size; i++){
            permuted[i] = i;
        }

        // shuffle the array
        for(int i=0; i<size; i++){
            int swap = (int) (Math.random() * size);
            int temp = permuted[swap];
            permuted[swap] = permuted[i];
            permuted[i] = temp;
        }
        // sort it
        long tstart = System.nanoTime();
        quicksort(permuted, 0, size-1);
        return System.nanoTime() - tstart;
    }

    public static void main(String[] args){
        int runs = 1000; // total # of tests to average over

        for(int n=2; n<=1e6; n*=2){
            // TESTING
            long tot_sorted = 0;
            long tot_random = 0;
            for(int i=0; i<runs; i++){
                tot_random += testRandom(n);
                tot_sorted += testSorted(n);
            }
            System.out.println(n+", "+tot_sorted+", "+tot_random);
        }

    }
}