Lua最长连续序列：集合判存的线性解法

local function longest(nums)
    table.sort(nums)                -- 全量排序，平方级比较浪费
    local best, cur, prev = 1, 1, nil
    for _, v in ipairs(nums) do
        cur = (v == prev + 1) and cur + 1 or 1
        best = math.max(best, cur)
        prev = v
    end
    return best
end

local function longest(nums)
    local set = {}
    for _, v in ipairs(nums) do set[v] = true end
    local best = 0
    for _, v in ipairs(nums) do
        if not set[v - 1] then      -- 段首才向右数
            local len, cur = 1, v
            while set[cur + 1] do
                cur = cur + 1
                len = len + 1
            end
            best = math.max(best, len)
        end
    end
    return best
end
sendmsg(actor, 1, "最长连续编号 "
    .. longest({100, 4, 200, 1, 3, 2}))