exercism

Exercism solutions.
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hamming.el (754B)

      1 ;;; hamming.el --- Hamming (exercism)
      2 
      3 ;;; Commentary:
      4 
      5 ;;; Code:
      6 
      7 (provide 'hamming)
      8 
      9 (defun count-different-chars(s1 s2)
     10   "Count the number of different characters between two strings, S1 and S2, which must be of equal length."
     11   (let ((count 0) (i 0))
     12     (while (< i (length s1))
     13       (if (not (char-equal (aref s1 i) (aref s2 i)))
     14           (setq count (+ count 1)))
     15       (setq i (+ i 1)))
     16     count))
     17 
     18 (defun hamming-distance(s1 s2)
     19   "Determine the Hamming distance of two strands of DNA.
     20 Expects the strands as two strings, S1 and S2,
     21 which must be of equal length."
     22   (cond ((string= s1 s2) 0)
     23         ((eq (length s1) (length s2)) (count-different-chars s1 s2))
     24         (error  "Strands must be of equal length")))
     25 
     26 ;;; hamming.el ends here