Family Day update

Task/Knapsack-problem-Bounded/00DESCRIPTION

@@ -8,7 +8,7 @@ The list contains which items are the wanted things for the trip, what is the we
 
 
 This is the list:
-{| style="text-align: left; width: 80%;" border="4" cellpadding="2" cellspacing="2"
+:::::{| style="text-align: left; width: 55%;" border="4" cellpadding="2" cellspacing="2"
 |+ Table of potential knapsack items
 |- style="background-color: rgb(255, 204, 255);"
 ! item !! weight (dag) (each) !! value (each) !! piece(s)

Task/Knapsack-problem-Bounded/Swift/knapsack-problem-bounded.swift

@@ -0,0 +1,82 @@
+public struct KnapsackItem: Hashable {
+  public var name: String
+  public var weight: Int
+  public var value: Int
+
+  public init(name: String, weight: Int, value: Int) {
+    self.name = name
+    self.weight = weight
+    self.value = value
+  }
+}
+
+public func knapsack(items: [KnapsackItem], limit: Int) -> [KnapsackItem] {
+  var table = Array(repeating: Array(repeating: 0, count: limit + 1), count: items.count + 1)
+
+  for j in 1...items.count {
+    let item = items[j-1]
+
+    for w in 1...limit {
+      if item.weight > w {
+        table[j][w] = table[j-1][w]
+      } else {
+        table[j][w] = max(table[j-1][w], table[j-1][w-item.weight] + item.value)
+      }
+    }
+  }
+
+  var result = [KnapsackItem]()
+  var w = limit
+
+  for j in stride(from: items.count, to: 0, by: -1) where table[j][w] != table[j-1][w] {
+    let item = items[j-1]
+
+    result.append(item)
+
+    w -= item.weight
+  }
+
+  return result
+}
+
+typealias GroupedItem = (name: String, weight: Int, val: Int, n: Int)
+
+let groupedItems: [GroupedItem] = [
+  ("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)
+]
+
+let items = groupedItems.flatMap({item in
+  (0..<item.n).map({_ in KnapsackItem(name: item.name, weight: item.weight, value: item.val) })
+})
+
+let bagged = knapsack(items: items, limit: 400)
+let (totalVal, totalWeight) = bagged.reduce((0, 0), {cur, item in (cur.0 + item.value, cur.1 + item.weight) })
+
+print("Bagged the following \(bagged.count) items:")
+
+for item in bagged {
+  print("\t\(item.name)")
+}
+
+print("For a total value of \(totalVal) and weight of \(totalWeight)")