A-M baby

Task/Knapsack-problem-Bounded/PicoLisp/knapsack-problem-bounded.l

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+(de *Items
+   ("map" 9 150 1)                     ("compass" 13 35 1)
+   ("water" 153 200 3)                 ("sandwich" 50 60 2)
+   ("glucose" 15 60 2)                 ("tin" 68 45 3)
+   ("banana" 27 60 3)                  ("apple" 39 40 3)
+   ("cheese" 23 30 1)                  ("beer" 52 10 3)
+   ("suntan cream" 11 70 1)            ("camera" 32 30 1)
+   ("t-shirt" 24 15 2)                 ("trousers" 48 10 2)
+   ("umbrella" 73 40 1)                ("waterproof trousers" 42 70 1)
+   ("waterproof overclothes" 43 75 1)  ("note-case" 22 80 1)
+   ("sunglasses" 7 20 1)               ("towel" 18 12 2)
+   ("socks" 4 50 1)                    ("book" 30 10 2) )
+
+# Dynamic programming solution
+(de knapsack (Lst W)
+   (when Lst
+      (cache '*KnapCache (pack (length Lst) ":" W)
+         (let X (knapsack (cdr Lst) W)
+            (if (ge0 (- W (cadar Lst)))
+               (let Y (cons (car Lst) (knapsack (cdr Lst) @))
+                  (if (> (sum caddr X) (sum caddr Y)) X Y) )
+               X ) ) ) ) )
+
+(let K
+   (knapsack
+      (mapcan                                   # Expand multiple items
+         '((X) (need (cadddr X) NIL X))
+         *Items )
+      400 )
+   (for I K
+      (apply tab I (3 -24 6 6) NIL) )
+   (tab (27 6 6) NIL (sum cadr K) (sum caddr K)) )