Task 1: Jumping Letters

You are given a word having alphabetic characters only, and a list of
positive integers of the same length

Write a script to print the new word generated after jumping forward
each letter in the given word by the integer in the list. The given list
would have exactly the number as the total alphabets in the given word.

Example 1

  Input: $word = 'Perl' and @jump = (2,22,19,9)
  Output: Raku

  'P' jumps 2 place forward and becomes 'R'.
  'e' jumps 22 place forward and becomes 'a'. (jump is cyclic i.e. after 'z' you go back to 'a')
  'r' jumps 19 place forward and becomes 'k'.
  'l' jumps 9 place forward and becomes 'u'.

Example 2

  Input: $word = 'Raku' and @jump = (24,4,7,17)
  Output: 'Perl'

MY NOTES: sounds very easy.  Essentially ROT(n) for a different value of n for
each letter.

GUEST LANGUAGE: As a bonus, I've had a go at translating ch-2.pl into C,
look in the C/ directory for that.


Task 2: Rearrange Groups

You are given a list of integers and group size greater than zero.

Write a script to split the list into equal groups of the given size where
integers are in sequential order. If it can't be done then print -1.

Example 1:

  Input: @list = (1,2,3,5,1,2,7,6,3) and $size = 3
  Output: (1,2,3), (1,2,3), (5,6,7)

Example 2:

  Input: @list = (1,2,3) and $size = 2
  Output: -1

Example 3:

  Input: @list = (1,2,4,3,5,3) and $size = 3
  Output: (1,2,3), (3,4,5)

Example 4:

Input: @list = (1,5,2,6,4,7) and $size = 3
Output: -1

MY NOTES: sounds reasonably easy as a brute force search.  But hang on, do we
need backtracking or not?  i.e. if you find a run-of-$size-consecutive-numbers
is that run necessarily a part of the solution, allowing you to extract any
run you find whether needing to backtrack?  no, not if that run is PART of a
longer run of consecutive numbers.  What if we only find run-of-$size-
consecutive-numbers isolated at the start, ie. where first(run)-1 is not
present in the input?  Then we should be able to: repeatedly pick any one run,
add it to solution, remove it from input, repeat until input is empty.

GUEST LANGUAGE: As a bonus, I've had a go at translating ch-2.pl into C,
look in the C/ directory for that.