alenaPy · Blackwoodseller · Feb 22, 2019
diff --git a/knapsack.py b/knapsack.py
@@ -0,0 +1,38 @@
+"""One-liner knapsack problem solution"""
+
+from collections import namedtuple
+import csv
+from itertools import accumulate
+from itertools import takewhile
+from itertools import tee
+
+
+thing = namedtuple('thing', 'item weight value')
+knapsack_capacity = 400
+
+# data preparation
+with open('knapsack_items_data', newline='') as data_file:
+    items = [thing(x[0], int(x[1]), int(x[2]))
+             for x in csv.reader(data_file, delimiter=',')]
+
+# First approach
+# Can be shorter in case of prepared ordered things list
+things = ([y.item for y in sorted(
+    items, key=lambda x: x.value / x.weight, reverse=True)[
+        :len([x for x in takewhile(
+            lambda x: x < knapsack_capacity,
+            accumulate(
+                [item.weight for item in sorted(
+                    items, key=lambda k: k.value / k.weight,
+                    reverse=True)]))])]])
+
+print(things)
+
+# Second approach
+things = [r[1].item for r in [
+    zip(takewhile(lambda y: y < knapsack_capacity,
+                  accumulate(item.weight for item in x[0])), x[1])
+    for x in [tee(sorted(items, key=lambda k: k.value / k.weight,
+                         reverse=True), 2)]][0]]
+
+print(things)
diff --git a/knapsack_items_data b/knapsack_items_data
@@ -0,0 +1,22 @@
+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