Global Alignment with Constant Gap Penalty solved by 496

Penalizing Large Insertions and Deletions

In dealing with global alignment in “Global Alignment with Scoring Matrix”, we encountered a linear gap penalty, in which the insertion or deletion of a gap is penalized by some constant times the length of the gap. However, this model is not necessarily the most practical model, as one large rearrangement could have inserted or deleted a long gap in a single step to transform one genetic string into another.

Problem

In a constant gap penalty, every gap receives some predetermined constant penalty, regardless of its length. Thus, the insertion or deletion of 1000 contiguous symbols is penalized equally to that of a single symbol.

Given: Two protein strings $s$ and $t$ in FASTA format (each of length at most 1000 aa).

Return: The maximum alignment score between $s$ and $t$. Use:

• The BLOSUM62 scoring matrix.
• Constant gap penalty equal to 5.

Sample Dataset

>Rosalind_79
PLEASANTLY
>Rosalind_41
MEANLY

Sample Output

13