【高级技巧】优先队列：任务调度的小顶堆实现封装

local heap = {}
local function siftUp(h, i)
    while i > 1 and h[i].ts < h[math.floor(i / 2)].ts do
        local p = math.floor(i / 2)
        h[i], h[p] = h[p], h[i]
        i = p
    end
end
local function siftDown(h, i)
    local n = #h
    while 2 * i <= n do
        local c = 2 * i
        if c < n and h[c + 1].ts < h[c].ts then
            c = c + 1
        end
        if h[i].ts <= h[c].ts then
            break
        end
        h[i], h[c] = h[c], h[i]
        i = c
    end
end
local function pushTask(h, task)
    h[#h + 1] = task
    siftUp(h, #h)
end
local function popTask(h)
    local top = h[1]
    h[1] = h[#h]
    table.remove(h)
    siftDown(h, 1)
    return top
end

local tasks = {}
pushTask(tasks, { ts = os.time() + 300, fn = function()
    print("5 分钟后执行")
end })
pushTask(tasks, { ts = os.time() + 60, fn = function()
    print("1 分钟后执行")
end })
while #tasks > 0 do
    if tasks[1].ts <= os.time() then
        local task = popTask(tasks)
        task.fn()
    else
        break
    end
end