require "table2"

local function s_of_n_creator(n)
    local s = table.rep(n, 0)
    local next = 1
    local m = n
    return function(item)
        if next <= n then
            s[next] = item
            next += 1
        else
            m += 1
            if math.random(m) <= n then
                local t = math.random(n)
                s[t] = item
                if next <= t then next = t + 1 end
            end
        end
        return s
    end
end

local freq = table.rep(10, 0)
for r = 0, 99_999 do
    local son = s_of_n_creator(3)
    for d = 48, 56 do son(d) end
    for son(57) as d do freq[d - 47] += 1 end
end
print(freq:concat(", "))