Lua滑动窗口：区间统计的进退维护

-- 错误：每个窗口从零重算，重复劳动翻倍
for i = k, #samples do
    local s = 0
    for j = i - k + 1, i do
        s = s + samples[j]
    end
    out[#out + 1] = s / k
end

local function slidingAvg(samples, k)
    local sum, out = 0, {}
    for i = 1, #samples do
        sum = sum + samples[i]
        if i > k then
            sum = sum - samples[i - k]
        end
        if i >= k then
            out[#out + 1] = sum / k
        end
    end
    return out
end
local label = panel:getChildByName("avgLabel")
label:setString(tostring(slidingAvg({1, 2, 3, 4, 5}, 3)[1]))