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| author | H.J <thechairman@thechairman.info> | 2024-10-09 11:36:55 -0400 |
|---|---|---|
| committer | H.J <thechairman@thechairman.info> | 2024-10-09 11:36:55 -0400 |
| commit | 8777ff071f7bb37631baa7b6717ad29961e50911 (patch) | |
| tree | 6d59c4ed58e454b960339c3d1151f0a879e8d7cb /racket/leetcode/lc-504-base7.rkt | |
| parent | 6156a9ef7be4012063a042aafb4e9b0d7eadde8e (diff) | |
| download | gleam_aoc-8777ff071f7bb37631baa7b6717ad29961e50911.tar.gz gleam_aoc-8777ff071f7bb37631baa7b6717ad29961e50911.zip | |
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Diffstat (limited to 'racket/leetcode/lc-504-base7.rkt')
| -rw-r--r-- | racket/leetcode/lc-504-base7.rkt | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/racket/leetcode/lc-504-base7.rkt b/racket/leetcode/lc-504-base7.rkt new file mode 100644 index 0000000..3e75052 --- /dev/null +++ b/racket/leetcode/lc-504-base7.rkt @@ -0,0 +1,16 @@ +#lang racket + +(define/contract (convert-to-base7 num) + (-> exact-integer? string?) + (define (max-base-power n base [pow 1]) + (cond [(n . = . (expt base pow)) pow] + [(n . < . (expt base pow)) (sub1 pow)] + [else (max-base-power n base (add1 pow))])) + (define (add-next-digit n pow acc) + (cond [(= pow 0) (string-append acc (number->string n))] + [else (add-next-digit (remainder n (expt 7 pow)) + (sub1 pow) + (string-append acc + (number->string (quotient n (expt 7 pow)))))])) + (string-append (if (negative? num) "-" "") + (add-next-digit (abs num) (max-base-power (abs num) 7) "")))
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