Partition list into equal parts, given the max size of each partition.

PartitionListEqually.java

    public static void main(String[] args) {
        // [[1, 2, 3]]
        System.out.println(partition(Arrays.asList(1, 2, 3), 4));

        // [[1, 2, 3, 4]]
        System.out.println(partition(Arrays.asList(1, 2, 3, 4), 4));

        // [[1, 2, 3], [4, 5]]
        System.out.println(partition(Arrays.asList(1, 2, 3, 4, 5), 4));

        // [[1, 2, 3], [4, 5, 6]]
        System.out.println(partition(Arrays.asList(1, 2, 3, 4, 5, 6), 4));

        // [[1, 2, 3, 4], [5, 6, 7]]
        System.out.println(partition(Arrays.asList(1, 2, 3, 4, 5, 6, 7), 4));

        // [[1, 2, 3, 4], [5, 6, 7, 8]]
        System.out.println(partition(Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8), 4));

        // [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
        System.out.println(partition(Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9), 4));

    }

    public static List<List<Integer>> partition(List<Integer> list, int maxN) {
        final int size = list.size();
        if (size == 0) {
            return Lists.newArrayList();
        }
        final int partitionCount = (size - 1) / maxN + 1;
        final int maxSizeInPartition = (size - 1) / partitionCount + 1;
        return Lists.partition(list, maxSizeInPartition);
    }