June 2018 Update

Task/Knapsack-problem-Bounded/Julia/knapsack-problem-bounded-1.julia

@@ -1,26 +1,27 @@
-using MathProgBase
+using MathProgBase, Cbc
 
-immutable KPDSupply{S<:String, T<:Integer}
-    item::S
+struct KPDSupply{T<:Integer}
+    item::String
     weight::T
     value::T
     quant::T
 end
+Base.show(io::IO, kdps::KPDSupply) = print(io, kdps.quant, " ", kdps.item, " ($(kdps.weight) kg, $(kdps.value) €)")
 
-function solve{S<:String, T<:Integer}(gear::Array{KPDSupply{S,T},1},
-                                      capacity::T)
-    w = map(x->x.weight, gear)
-    v = map(x->x.value, gear)
-    q = map(x->x.quant, gear)
-    sol = mixintprog(-v, w', '<', capacity, :Int, 0, q)
-    sol.status == :Optimal || error("This Problem could not be solved")
-    if all(q .== 1)
-        return gear[sol.sol .== 1.0]
+function solve(gear::Vector{KPDSupply{T}}, capacity::Integer) where T<:Integer
+    w = getfield.(gear, :weight)
+    v = getfield.(gear, :value)
+    q = getfield.(gear, :quant)
+    sol = mixintprog(-v, w', '<', capacity, :Int, 0, q, CbcSolver())
+    sol.status == :Optimal || error("this problem could not be solved")
+
+    if all(q .== 1) # simpler case
+        return gear[sol.sol == 1.0]
     else
-        pack = KPDSupply[]
-        s = int(sol.sol)
+        pack = similar(gear, 0)
+        s = round.(Int, sol.sol)
         for (i, g) in enumerate(gear)
-            s[i] != 0 || continue
+            iszero(s[i]) && continue
             push!(pack, KPDSupply(g.item, g.weight, g.value, s[i]))
         end
         return pack

Task/Knapsack-problem-Bounded/Julia/knapsack-problem-bounded-2.julia

@@ -22,11 +22,6 @@ gear = [KPDSupply("map", 9, 150, 1),
         KPDSupply("book", 30, 10, 2)]
 
 pack = solve(gear, 400)
-
-println("The hiker should pack:")
-for s in pack
-    println("    ", s.quant, " ", s.item)
-end
-println()
-println("Packed Weight:  ", mapreduce(x->x.weight*x.quant, +, pack))
-println("Packed Value:  ", mapreduce(x->x.value*x.quant, +, pack))
+println("The hiker should pack: \n - ", join(pack, "\n - "))
+println("\nPacked weight: ", sum(getfield.(pack, :weight)), " kg")
+println("Packed value: ", sum(getfield.(pack, :value)), " €")