require "table2"
local fmt = require "fmt"

class item
    function __construct(public name, public value, public weight, public volume)
    end
end

local items = {
    new item("panacea", 3000, 0.3, 0.025),
    new item("ichor", 1800, 0.2, 0.015),
    new item("gold", 2500, 2, 0.002)
}

local n = #items
local count = table.rep(n, 0)
local best  = table.rep(n, 0)
local best_value = 0
local max_weight = 25
local max_volume = 0.25

local function knapsack(i, value, weight, volume)
    if i == n + 1 then
        if value > best_value then
            best_value = value
            for j = 1, n do best[j] = count[j] end
        end
        return
    end
    local m1 = weight // items[i].weight
    local m2 = volume // items[i].volume
    count[i] = math.min(m1, m2)
    while count[i] >= 0 do
        knapsack(
            i + 1,
            value  + count[i] * items[i].value,
            weight - count[i] * items[i].weight,
            volume - count[i] * items[i].volume
        )
        count[i] -= 1
    end
end

knapsack(1, 0, max_weight, max_volume)
print("Item Chosen  Number Value  Weight  Volume")
print("-----------  ------ -----  ------  ------")
local item_count = 0
local sum_number = 0
local sum_weight = 0
local sum_volume = 0
for i = 1, n do
    if best[i] != 0 then
        item_count  += 1
        local name   = items[i].name
        local number = best[i]
        local value  = items[i].value  * number
        local weight = items[i].weight * number
        local volume = items[i].volume * number
        sum_number  += number
        sum_weight  += weight
        sum_volume  += volume
        local f = "%-11s   %2d    %5.0f   %4.1f    %4.2f"
        fmt.print(f, name, number, value, weight, volume)
    end
end
print("-----------  ------ -----  ------  ------")
local f = "%d items       %2d    %5.0f   %4.1f    %4.2f"
fmt.print(f, item_count, sum_number, best_value, sum_weight, sum_volume)