SAFEGUARD

local range = 20
local whitelist = {}

if not commands then
    error("Not running on command computer")
end

local success, obj = commands.exec("scoreboard objectives list")
if success == true then
    local found = false
    for i,v in pairs(obj) do
        if v == "Whitelisted33" then
            found = true
        end
    end
    if found == false then
        commands.execAsync("scoreboard objectives add Whitelisted33 dummy")
    end
else
    commands.execAsync("scoreboard objectives add Whitelisted33 dummy")
end

for i,v in pairs(whitelist) do
    commands.execAsync("scoreboard players set "..v.." Whitelisted33 1")
end

while true do
    commands.execAsync("gamemode adventure @a[m=1,r="..range..",score_Whitelisted33=0]")
    commands.execAsync("gamemode adventure @a[m=0,r="..range..",score_Whitelisted33=0]")
    commands.execAsync("gamemode survival @a[rm="..range+(1)..",r="..range+(11)..",m=2,score_Whitelisted33=0]")
    sleep(0.5)
end