public int minFactory(int[] array, int range) {
        int i = 0;
        int count = 0;
        int start = 0;
        while (i < array.length && i <= range) {
            if (array[i] == 1) {
                start = i;
            }
            i++;
        }
        if (start == 0 && array[0] == 0) return -1;
        count++;
        while (start + range + 1 < array.length) {
            start = farMostFactory(array, start, range);
            if (start == -1) return -1;
            count++;
        }
        return count;
    }
    private int farMostFactory(int[] array, int start, int range) {
        int i = start + 1; int pos = start;
       // if (start + 1 + range >= array.length) return array.length; // The start 1 can cover to the end
        while (i < array.length && i - start <= 2 * range + 1) {
            if (array[i] == 1) {
                pos = i;
            }
            i++;
        }
        if (pos == start) return -1;
        return pos;
    }