"Hardness" of (multi-) sequence alignment
Align 2 sequences of length N allowing gaps.
AC-ACCATA , A-----CACCATA , etc.
2N gap positions, gap lengths of 0 to N each:
A naïve algorithm might scale by O(N2N).
For N= 3x109 this is rather large.
Now, what about kɮ sequences?
or rearrangements other than gaps?