Merge Sort

gistfile1.java

<T> void mergeSort(T[] a, Comparator<T> c) {
        if (a.length <= 1) return;
        T[] a0 = Arrays.copyOfRange(a, 0, a.length/2);
        T[] a1 = Arrays.copyOfRange(a, a.length/2, a.length);
        mergeSort(a0, c);
        mergeSort(a1, c);
        merge(a0, a1, a, c);
    }
    
    
     <T> void merge(T[] a0, T[] a1, T[] a, Comparator<T> c) {
        int i0 = 0, i1 = 0;
        for (int i = 0; i < a.length; i++) {
            if (i0 == a0.length)
                a[i] = a1[i1++];
            else if (i1 == a1.length)
                a[i] = a0[i0++];
            else if (compare(a0[i0], a1[i1]) < 0)
                a[i] = a0[i0++];
            else 
                a[i] = a1[i1++];
        }
    }