Good algorithm for combining items from N lists into one with balanced distribution?

Question

Let\'s say I have the three following lists

A1
A2
A3

B1
B2

C1
C2
C3
C4
C5

I\'d like to combine them into a si

Answer 1

• Make a hash table of lists.
• For each list, store the nth element in the list under the key (/ n (+ (length list) 1))
• Optionally, shuffle the lists under each key in the hash table, or sort them in some way
• Concatenate the lists in the hash by sorted key