RosettaCodeData/Task/Knapsack-problem-Unbounded/Wren/knapsack-problem-unbounded.wren
2023-12-16 21:33:55 -08:00

77 lines
2.1 KiB
Text

import "./fmt" for Fmt
class Item {
construct new(name, value, weight, volume) {
_name = name
_value = value
_weight = weight
_volume = volume
}
name { _name }
value { _value }
weight { _weight }
volume { _volume }
}
var items = [
Item.new("panacea", 3000, 0.3, 0.025),
Item.new("ichor", 1800, 0.2, 0.015),
Item.new("gold", 2500, 2, 0.002)
]
var n = items.count
var count = List.filled(n, 0)
var best = List.filled(n, 0)
var bestValue = 0
var maxWeight = 25
var maxVolume = 0.25
var knapsack // recursive
knapsack = Fn.new { |i, value, weight, volume|
if (i == n) {
if (value > bestValue) {
bestValue = value
for (j in 0...n) best[j] = count[j]
}
return
}
var m1 = (weight / items[i].weight).floor
var m2 = (volume / items[i].volume).floor
count[i] = m1.min(m2)
while (count[i] >= 0) {
knapsack.call(
i + 1,
value + count[i] * items[i].value,
weight - count[i] * items[i].weight,
volume - count[i] * items[i].volume
)
count[i] = count[i] - 1
}
}
knapsack.call(0, 0, maxWeight, maxVolume)
System.print("Item Chosen Number Value Weight Volume")
System.print("----------- ------ ----- ------ ------")
var itemCount = 0
var sumNumber = 0
var sumWeight = 0
var sumVolume = 0
for (i in 0... n) {
if (best[i] != 0) {
itemCount = itemCount + 1
var name = items[i].name
var number = best[i]
var value = items[i].value * number
var weight = items[i].weight * number
var volume = items[i].volume * number
sumNumber = sumNumber + number
sumWeight = sumWeight + weight
sumVolume = sumVolume + volume
Fmt.write("$-11s $2d $5.0f $4.1f", name, number, value, weight)
Fmt.print(" $4.2f", volume)
}
}
System.print("----------- ------ ----- ------ ------")
Fmt.write("$d items $2d $5.0f $4.1f", itemCount, sumNumber, bestValue, sumWeight)
Fmt.print(" $4.2f", sumVolume)