solution to 4.41 and 4.42

[sicp.git] / src / sicp / ex4_41.rkt

diff --git a/src/sicp/ex4_41.rkt b/src/sicp/ex4_41.rkt
new file mode 100644 (file)
index 0000000..ba4b97b
--- /dev/null
+++ b/src/sicp/ex4_41.rkt
@@ -0,0 +1,24 @@
+#lang racket
+(require "distinct.rkt")
+
+(define (multiple-dwelling)
+  (for/list ([baker '(1 2 3 4 5)]
+             #:unless (= baker 5)
+             [cooper '(1 2 3 4 5)]
+             #:unless (= cooper 1)
+             [fletcher '(1 2 3 4 5)]
+             #:unless (or (= fletcher 1)
+                          (= fletcher 5))
+             [miller '(3 4 5)]
+             #:when (> miller cooper)
+             [smith '(1 2 3 4 5)]
+             #:when (and (not (= (abs (- smith fletcher)) 1))
+                         (not (= (abs (- fletcher cooper)) 1))
+                         (distinct? (list baker cooper fletcher miller smith))))
+    (list (list 'baker baker)
+          (list 'cooper cooper)
+          (list 'fletcher fletcher)
+          (list 'miller miller)
+          (list 'smith smith))))
+
+(multiple-dwelling)
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