Another update from ingydotnet^djgoku

Task/Knapsack-problem-0-1/Python/knapsack-problem-0-1-3.py

@@ -0,0 +1,36 @@
+def total_value(items, max_weight):
+    return  sum([x[2] for x in items]) if sum([x[1] for x in items]) < max_weight else 0
+
+cache = {}
+def solve(items, max_weight):
+    if not items:
+        return ()
+    if (items,max_weight) not in cache:
+        head = items[0]
+        tail = items[1:]
+        include = (head,) + solve(tail, max_weight - head[1])
+        dont_include = solve(tail, max_weight)
+        if total_value(include, max_weight) > total_value(dont_include, max_weight):
+            answer = include
+        else:
+            answer = dont_include
+        cache[(items,max_weight)] = answer
+    return cache[(items,max_weight)]
+
+items = (
+    ("map", 9, 150), ("compass", 13, 35), ("water", 153, 200), ("sandwich", 50, 160),
+    ("glucose", 15, 60), ("tin", 68, 45), ("banana", 27, 60), ("apple", 39, 40),
+    ("cheese", 23, 30), ("beer", 52, 10), ("suntan cream", 11, 70), ("camera", 32, 30),
+    ("t-shirt", 24, 15), ("trousers", 48, 10), ("umbrella", 73, 40),
+    ("waterproof trousers", 42, 70), ("waterproof overclothes", 43, 75),
+    ("note-case", 22, 80), ("sunglasses", 7, 20), ("towel", 18, 12),
+    ("socks", 4, 50), ("book", 30, 10),
+    )
+max_weight = 400
+
+solution = solve(items, max_weight)
+print "items:"
+for x in solution:
+    print x[0]
+print "value:", total_value(solution, max_weight)
+print "weight:", sum([x[1] for x in solution])