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-989-add-to-array-form.rkt | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) create mode 100644 leetcode/lc-989-add-to-array-form.rkt (limited to 'leetcode/lc-989-add-to-array-form.rkt') diff --git a/leetcode/lc-989-add-to-array-form.rkt b/leetcode/lc-989-add-to-array-form.rkt new file mode 100644 index 0000000..c88bdc9 --- /dev/null +++ b/leetcode/lc-989-add-to-array-form.rkt @@ -0,0 +1,24 @@ +#lang racket +(define/contract (add-to-array-form num k) + (-> (listof exact-integer?) exact-integer? (listof exact-integer?)) + (define rev-num (reverse num)) + (define raw-array-form + (cond [(= k 0) num] + [else + (for/fold ([sum-list '()] + [addend k] + [carry 0] + #:result sum-list) + ([place (append rev-num + (make-list (add1 (order-of-magnitude k)) 0))]) + (let* ([place-sum (+ place carry (modulo addend 10))] + [to-carry (quotient place-sum 10)] + [new-place (modulo place-sum 10)]) + (values (cons new-place sum-list) + (quotient addend 10) + to-carry)))])) + (match-define-values + (result _) (drop-common-prefix raw-array-form + (make-list (length raw-array-form) 0))) + (cond [(empty? result) '(0)] + [else result])) \ No newline at end of file -- cgit v1.2.3