071-reverse-groups

Reverse Groups

Challenge Description:

Given a list of numbers and a positive integer k, reverse the elements of the list, k items at a time. If the number of elements is not a multiple of k, then the remaining items in the end should be left as is.

Input sample:

Your program should accept as its first argument a path to a filename. Each line in this file contains a list of numbers and the number k, separated by a semicolon. The list of numbers are comma delimited. E.g.

1,2,3,4,5;2
1,2,3,4,5;3

Output sample:

Print out the new comma separated list of numbers obtained after reversing. E.g.

2,1,4,3,5
3,2,1,4,5