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| -rw-r--r-- | codewars/7-kyu/a-rule-of-divisibility-by-7/solution.rkt | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/codewars/7-kyu/a-rule-of-divisibility-by-7/solution.rkt b/codewars/7-kyu/a-rule-of-divisibility-by-7/solution.rkt new file mode 100644 index 0000000..6859107 --- /dev/null +++ b/codewars/7-kyu/a-rule-of-divisibility-by-7/solution.rkt @@ -0,0 +1,15 @@ +#lang racket + +;; https://www.codewars.com/kata/55e6f5e58f7817808e00002e + +(provide seven) + +(define (seven m) + (define (impl cur steps) + (define x (quotient cur 10)) + (define y (modulo cur 10)) + (define next (- x (* 2 y))) + (if (< cur 100) + (cons cur steps) + (impl next (+ 1 steps)))) + (impl m 0)) |