Levenshtein distance allowing one swap of adjacent chars as unit cost.
DamerauLevenshteinDistance[u, v]
DamerauLevenshteinDistance["abc", "cba"]
→ 2DamerauLevenshteinDistance[{1, 0, 0, 1, 1}, {0, 0, 1, 0, 1}]
→ 2DamerauLevenshteinDistance[BioSequence["DNA", "CGCATAG"], BioSequence["DNA", "GCATGA"]]
→ 2