Data commit

Task/Knapsack-problem-Bounded/Python/knapsack-problem-bounded-2.py

@@ -0,0 +1,66 @@
+from itertools import groupby
+
+try:
+    xrange
+except:
+    xrange = range
+
+maxwt = 400
+
+groupeditems = (
+            ("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),
+           )
+items = sum( ([(item, wt, val)]*n for item, wt, val,n in groupeditems), [])
+
+def knapsack01_dp(items, limit):
+    table = [[0 for w in range(limit + 1)] for j in xrange(len(items) + 1)]
+
+    for j in xrange(1, len(items) + 1):
+        item, wt, val = items[j-1]
+        for w in xrange(1, limit + 1):
+            if wt > w:
+                table[j][w] = table[j-1][w]
+            else:
+                table[j][w] = max(table[j-1][w],
+                                  table[j-1][w-wt] + val)
+
+    result = []
+    w = limit
+    for j in range(len(items), 0, -1):
+        was_added = table[j][w] != table[j-1][w]
+
+        if was_added:
+            item, wt, val = items[j-1]
+            result.append(items[j-1])
+            w -= wt
+
+    return result
+
+
+bagged = knapsack01_dp(items, maxwt)
+print("Bagged the following %i items\n  " % len(bagged) +
+      '\n  '.join('%i off: %s' % (len(list(grp)), item[0])
+                  for item,grp in groupby(sorted(bagged))))
+print("for a total value of %i and a total weight of %i" % (
+    sum(item[2] for item in bagged), sum(item[1] for item in bagged)))