From fafbeaf9e3c09ba7a5bea7e47d5736001f8a5aa1 Mon Sep 17 00:00:00 2001 From: HJ Date: Tue, 17 Jan 2023 12:46:04 -0500 Subject: adding old leetcode solutions --- leetcode/lc-504-base7.rkt | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) create mode 100644 leetcode/lc-504-base7.rkt (limited to 'leetcode/lc-504-base7.rkt') diff --git a/leetcode/lc-504-base7.rkt b/leetcode/lc-504-base7.rkt new file mode 100644 index 0000000..3e75052 --- /dev/null +++ b/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) ""))) \ No newline at end of file -- cgit v1.2.3