23 lines
1.2 KiB
Racket
23 lines
1.2 KiB
Racket
#lang racket
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;;; reads a licence file on standard input
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;;; returns max licences used and list of times this occurred
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(define (count-licences)
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(define (sub-count-licences)
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(for/fold ((in-use 0) (max-in-use 0) (times-list null))
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((ln (in-lines)))
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(let ((mtch (regexp-match #px"License (IN |OUT) @ (.*) for job.*" ln)))
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(cond
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[(string=? "OUT" (second mtch))
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(let ((in-use+1 (add1 in-use)))
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(cond
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[(> in-use+1 max-in-use) (values in-use+1 in-use+1 (list (third mtch)))]
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[(= in-use+1 max-in-use) (values in-use+1 max-in-use (cons (third mtch) times-list))]
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[else (values in-use+1 max-in-use times-list)]))]
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[(string=? "IN " (second mtch)) (values (sub1 in-use) max-in-use times-list)]
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[else (values in-use max-in-use times-list)]))))
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(let-values (((in-use max-in-use times-list) (sub-count-licences)))
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(values max-in-use (reverse times-list))))
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(define-values (max-used max-used-when) (with-input-from-file "mlijobs.txt" count-licences))
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(printf "Maximum licences in simultaneously used is ~a at the following times:~%" max-used)
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(for-each displayln max-used-when)
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