ハミング距離
For any pair of length-formula_4 words formula_15 and formula_9 over formula_5, the Hamming distance formula_18 is the number of positions formula_19 at which formula_20. Further, define "reverse-Hamming distance" as formula_21. Similarly, "reverse-complement Hamming distance" is formula_22. (where formula_23 stands for "reverse complement")