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62 lines
1.9 KiB
Racket
62 lines
1.9 KiB
Racket
#lang at-exp racket
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(require "csp.rkt" rackunit)
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(define demo (make-csp))
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(add-vars! demo '(t w) (range 7))
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(add-var! demo 'o '(2 6 7))
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(define (sum-three t w o) (= 3 (+ t w o)))
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(add-constraint! demo sum-three '(t w o))
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(add-constraint! demo alldiff '(t w o))
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(add-constraint! demo < '(t w o))
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(check-equal? (solve demo) ($csp (list ($var 'o '(2)) ($var 'w '(1)) ($var 't '(0))) '()))
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;; TWO + TWO = FOUR
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(define ttf (make-csp))
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(add-vars! ttf '(t w o f u r c10 c100) (range 10))
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(add-constraint! ttf alldiff '(t w o f u r))
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(define (adder arg1 arg2 ones-digit tens-digit)
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(= (+ arg1 arg2) (+ (* 10 tens-digit) ones-digit)))
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(add-constraint! ttf adder '(o o r c10))
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(add-constraint! ttf adder '(w w u c100))
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(add-constraint! ttf adder '(t t o f))
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(add-constraint! ttf positive? '(f))
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(define ttf-solution (solve ttf))
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(check-equal? ttf-solution
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($csp
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(list
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($var 'c100 '(0))
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($var 'c10 '(0))
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($var 'r '(8))
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($var 'u '(6))
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($var 'f '(1))
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($var 'o '(4))
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($var 'w '(3))
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($var 't '(7)))
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'()))
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(define (ttf-print csp)
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(format "~a~a~a + ~a~a~a = ~a~a~a~a" ($csp-ref csp 't) ($csp-ref csp 'w) ($csp-ref csp 'o) ($csp-ref csp 't) ($csp-ref csp 'w) ($csp-ref csp 'o) ($csp-ref csp 'f) ($csp-ref csp 'o) ($csp-ref csp 'u) ($csp-ref csp 'r)))
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(check-equal? (solve ttf-solution ttf-print) "734 + 734 = 1468")
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;; ABC problem:
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;; what is the minimum value of
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;; ABC
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;; -------
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;; A+B+C
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(define abc (make-csp))
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(add-vars! abc '(a b c) (range 1 10))
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(define (test-solution s) (let ([a (car ($csp-vals abc 'a))]
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[b (car ($csp-vals abc 'b))]
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[c (car ($csp-vals abc 'c))])
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(/ (+ (* 100 a) (* 10 b) c) (+ a b c))))
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;; todo: gather all solutins in generator
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(test-solution (solve abc)) |