霍夫曼树和霍夫曼编码

一、定义

霍夫曼树

又称最优二叉树，是一种带权路径长度最短的二叉树。所谓树的带权路径长度，就是树中所有的叶结点的权值乘上其到根结点的路径长度（若根结点为0层，叶结点到根结点的路径长度为叶结点的层数）。树的路径长度是从树根到每一结点的路径长度之和，记为 WPL =（W1*L1 + W2*L2 + W3*L3 +...+ Wn*Ln），N个权值 Wi（i=1,2,...n）构成一棵有N个叶结点的二叉树，相应的叶结点的路径长度为 Li（i=1,2,...n）。可以证明霍夫曼树的 WPL 是最小的。

霍夫曼编码

是一种基于霍夫曼树的用于无损数据压缩的熵编码（权编码）算法。

由于霍夫曼树具[……]

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二叉堆计算动态中位数

要求

最近在刷算法，遇到一个有意思的题，要求如下：

设计一个数据结构，可随时插入节点，且随时查询节点集合的中位数，要求插入节点的时间复杂度为 O(logN)，查询中位数的时间复杂度为 O(1)。

中位数定义：节点个数为奇数个时，为有序情况下集合的中间节点；偶数时，为中间两节点的平均值。

分析

求中位数，直觉的做法是先排序，然后根据数组的长度算出中位数，根据算法不同时间复杂度从 O(n) ~ O(NlogN) 不等。但这只适用于元素数目不变的情况，对可动态添加节点的情况，需要做到：

在插入时便进行重排序，时间复杂度为 O(logN)
不论节点个数奇偶，查中位数时间复[……]

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岁末总结

岁末将至，且参照去年的格式，炮制一篇年度总结：

看了 71 部电影，比上一年减少了 41 部
看了书 21 本，比上一年增加了3本
听了 299 张专辑，比一年增加了144张（大部分是古典 🙂

生活就似这浮浮沉沉的数据，不算太好，也没有更糟。

大的收获：

我和孙老师正式结合成为了夫妻
蜜月我第一次出国，目的地东京，非常美妙的旅程

大的调整：

毅然放弃了舒适的工作环境，去到一家更为初创的公司，出任技术负责人

满打满算，我到这家初创 k12 公司，足有三个月，我以一个技术人的思维和韧劲，对这支半自动化的技术队伍进[……]

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SOCKS5 协议解析

意图

SOCKS5 是一个代理协议，旨在为位于 Intranet 防火墙后的用户提供访问 Internet 的代理服务（Intranet，你没听错，这是个有一定年头的协议，其 RFC 提案的时间比 HTTP 1.0 还要早两个月）。

代理

根据 HTTP 1.1 的定义，proxy 是：

An intermediary program which acts as both a server and a client for the purpose of making requests on behalf of other clients. Requests are servic[……]

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应用 Locust 快速上手写压测

引子

做为一个压测工具（库），locust 其实解决这么一个问题：AB 之类压测工具不能编写复杂的因果逻辑，而现实场景中，待压的服务往往是有一套完整执行流程的，比如 APP 要访问一个 API，是需要先鉴权（验明不是非 APP 访问），再登录换 Token，然后才是 API 调用……

这一切，在 locust 中都很容易实现，本质上，应用 locust 做压测，就是在写 Python 程序，只是它集成了一套不错的 UI，外加并发的benchmark功能。

至于写个压测为什么要用Python，是因为：这玩意心智负担低，你谷歌SO复制粘贴一把梭，直接上手就能写，大脑无需切换cont[……]

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goroutine, channel 和 CSP

引子

老听 clojure 社区的人提起 core.async ，说它如何好用，如何简化了并发编程的模型，不由得勾起了我的好奇心，想了解一番其思想的源头：CSP 模型及受其启发的 goroutine 和 channel 。

CSP 模型

CSP 描述这样一种并发模型：多个Process 使用一个 Channel 进行通信, 这个 Channel 连结的 Process 通常是匿名的，消息传递通常是同步的（有别于 Actor Model）。

CSP 最早是由 Tony Hoare 在 1977 年提出，据说老爷子至今仍在更新这个理论模型，有兴趣的朋友可以自行查阅电子版本：http:[……]

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在 Node.js 中提供 gRPC 服务

引子

Web APP 的大行其道导致了 API 架构的流行，大量站点及服务使用基于 HTTP 1.1 的API 进行交互。这一类文本传输型 API 的优点很突出：易于编写和理解；支持异构平台的沟通。缺点也很明显：基于文本从而导致API传输内容过于庞大；存在客户端易感知的延迟。

如果对性能有所要求，不妨试试基于二进制传输的RPC框架，比如：

gRPC

gRPC 是一个高性能、开源的、通用的、面向移动端的 RPC 框架，传输协议基于 HTTP/2，这意味着它支持双向流、流控、头部压缩、单 TCP 连接上的请求多路复用等特性。

接口层面，gRPC默认使用 Protocol Bu[……]

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WebSocket 的鉴权授权方案

引子

WebSocket 是个好东西，为我们提供了便捷且实时的通讯能力。然而，对于 WebSocket 客户端的鉴权，协议的 RFC 是这么说的：

This protocol doesn’t prescribe any particular way that servers can
authenticate clients during the WebSocket handshake. The WebSocket
server can use any client authentication mechanism available to a
generic HTTP server,[……]

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算法复杂度和大O表示法

概念

算法复杂度是算法分析里的概念（对应到SICP里的增长阶），是衡量计算资源消耗数量（例如计算时间，存储器使用等）的指标。

算法的复杂度在理论上表示为一个函数：其定义域是输入数据的长度（通常考虑任意大的输入，没有上界），值域通常是执行步骤数量（时间复杂度）或者存储器位置数量（空间复杂度）。

这个函数形如：

R(n) = Θ(f(n)) 亦可记做 O(f(n))

f(n) 就是被度量的算法主体；算法的复杂度标记就是大O（Θ读做theta），这种记法称为大O表示法。

常见复杂度级别

Θ(1) 常数级别
Θ(log(n)) 对数级别
Θ(n) 线性级别

[……]

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八皇后问题的Julia实现

问题

八皇后问题是一个以国际象棋为背景的问题：如何能够在8×8的国际象棋棋盘上放置八个皇后，使得任何一个皇后都无法直接吃掉其他的皇后？

尝试使用Julia实现一个回溯解：

实现

回溯法进行暴力查找：

function find_safe_coord(board::Array{Int}, curr_row, n; trace_back=false)
    start = 1
    if trace_back
        start = board[curr_row] + 1
    end
    for col = start : n
        has_menace = false
        for row = 1 : curr_row - 1
            prev = board[row]
            if prev == col || curr_row - row  == abs(col - prev)
                has_menace = true
            end
        end
        !has_menace && return col
    end
    nothing
end

function n_queens_puzzle(n)
    board = zeros(Int, n)
    curr_row = 1
    while curr_row <= n
        coord = find_safe_coord(board, curr_row, n)
        if coord != nothing
            board[curr_row] = coord
            curr_row == n && produce(copy(board))
        end
        if coord == nothing || curr_row == n
            while true
                curr_row -= 1
                curr_row == 0 && return produce(nothing)
                coord = find_safe_coord(board, curr_row, n, trace_back=true)
                if coord != nothing
                    board[curr_row] = coord
                    break
                end
            end
        end
        curr_row += 1
    end
end

# 逐行输出[x,y]
solutions = @task n_queens_puzzle(8)
for solution in solutions
    if solution != nothing
        for row in eachindex(solution)
            print("[$row,$(solution[row])] ")
        end
        println()
    end
end

function find_safe_coord(board::Array{Int}, curr_row, n; trace_back=false)

start = 1

if trace_back

start = board[curr_row] + 1

end

for col = start : n

has_menace = false

for row = 1 : curr_row - 1

prev = board[row]

if prev == col || curr_row - row == abs(col - prev)

has_menace = true

end

!has_menace && return col

end

nothing

end

function n_queens_puzzle(n)

board = zeros(Int, n)

curr_row = 1

while curr_row <= n

coord = find_safe_coord(board, curr_row, n)

if coord != nothing

board[curr_row] = coord

curr_row == n && produce(copy(board))

end

if coord == nothing || curr_row == n

while true

curr_row -= 1

curr_row == 0 && return produce(nothing)

coord = find_safe_coord(board, curr_row, n, trace_back=true)

if coord != nothing

board[curr_row] = coord

break

end

curr_row += 1

end

# 逐行输出[x,y]

solutions = @task n_queens_puzzle(8)

for solution in solutions

if solution != nothing

for row in eachindex(solution)

print("[$row,$(solution[row])] ")

end

println()

end

很可惜，我的代码高亮插件不支持Julia的语法 🙁

输出

[1,1] [2,5] [3,8] [4,6] [5,3] [6,7] [7,2] [8,4]
[1,1] [2,6] [3,8] [4,3] [5,7] [6,4] [7,2] [8,5]
[1,1] [2,7] [3,4] [4,6] [5,8] [6,2] [7,5] [8,3]
[1,1] [2,7] [3,5] [4,8] [5,2] [6,4] [7,6] [8,3]
[1,2] [2,4] [3,6] [4,8] [5,3] [6,1] [7,7] [8,5]
[1,2] [2,5] [3,7] [4,1] [5,3] [6,8] [7,6] [8,4]
[1,2] [2,5] [3,7] [4,4] [5,1] [6,8] [7,6] [8,3]
[1,2] [2,6] [3,1] [4,7] [5,4] [6,8] [7,3] [8,5]
[1,2] [2,6] [3,8] [4,3] [5,1] [6,4] [7,7] [8,5]
[1,2] [2,7] [3,3] [4,6] [5,8] [6,5] [7,1] [8,4]
[1,2] [2,7] [3,5] [4,8] [5,1] [6,4] [7,6] [8,3]
[1,2] [2,8] [3,6] [4,1] [5,3] [6,5] [7,7] [8,4]
[1,3] [2,1] [3,7] [4,5] [5,8] [6,2] [7,4] [8,6]
[1,3] [2,5] [3,2] [4,8] [5,1] [6,7] [7,4] [8,6]
[1,3] [2,5] [3,2] [4,8] [5,6] [6,4] [7,7] [8,1]
[1,3] [2,5] [3,7] [4,1] [5,4] [6,2] [7,8] [8,6]
[1,3] [2,5] [3,8] [4,4] [5,1] [6,7] [7,2] [8,6]
[1,3] [2,6] [3,2] [4,5] [5,8] [6,1] [7,7] [8,4]
[1,3] [2,6] [3,2] [4,7] [5,1] [6,4] [7,8] [8,5]
[1,3] [2,6] [3,2] [4,7] [5,5] [6,1] [7,8] [8,4]
[1,3] [2,6] [3,4] [4,1] [5,8] [6,5] [7,7] [8,2]
[1,3] [2,6] [3,4] [4,2] [5,8] [6,5] [7,7] [8,1]
[1,3] [2,6] [3,8] [4,1] [5,4] [6,7] [7,5] [8,2]
[1,3] [2,6] [3,8] [4,1] [5,5] [6,7] [7,2] [8,4]
[1,3] [2,6] [3,8] [4,2] [5,4] [6,1] [7,7] [8,5]
[1,3] [2,7] [3,2] [4,8] [5,5] [6,1] [7,4] [8,6]
[1,3] [2,7] [3,2] [4,8] [5,6] [6,4] [7,1] [8,5]
[1,3] [2,8] [3,4] [4,7] [5,1] [6,6] [7,2] [8,5]
[1,4] [2,1] [3,5] [4,8] [5,2] [6,7] [7,3] [8,6]
[1,4] [2,1] [3,5] [4,8] [5,6] [6,3] [7,7] [8,2]
[1,4] [2,2] [3,5] [4,8] [5,6] [6,1] [7,3] [8,7]
[1,4] [2,2] [3,7] [4,3] [5,6] [6,8] [7,1] [8,5]
[1,4] [2,2] [3,7] [4,3] [5,6] [6,8] [7,5] [8,1]
[1,4] [2,2] [3,7] [4,5] [5,1] [6,8] [7,6] [8,3]
[1,4] [2,2] [3,8] [4,5] [5,7] [6,1] [7,3] [8,6]
[1,4] [2,2] [3,8] [4,6] [5,1] [6,3] [7,5] [8,7]
[1,4] [2,6] [3,1] [4,5] [5,2] [6,8] [7,3] [8,7]
[1,4] [2,6] [3,8] [4,2] [5,7] [6,1] [7,3] [8,5]
[1,4] [2,6] [3,8] [4,3] [5,1] [6,7] [7,5] [8,2]
[1,4] [2,7] [3,1] [4,8] [5,5] [6,2] [7,6] [8,3]
[1,4] [2,7] [3,3] [4,8] [5,2] [6,5] [7,1] [8,6]
[1,4] [2,7] [3,5] [4,2] [5,6] [6,1] [7,3] [8,8]
[1,4] [2,7] [3,5] [4,3] [5,1] [6,6] [7,8] [8,2]
[1,4] [2,8] [3,1] [4,3] [5,6] [6,2] [7,7] [8,5]
[1,4] [2,8] [3,1] [4,5] [5,7] [6,2] [7,6] [8,3]
[1,4] [2,8] [3,5] [4,3] [5,1] [6,7] [7,2] [8,6]
[1,5] [2,1] [3,4] [4,6] [5,8] [6,2] [7,7] [8,3]
[1,5] [2,1] [3,8] [4,4] [5,2] [6,7] [7,3] [8,6]
[1,5] [2,1] [3,8] [4,6] [5,3] [6,7] [7,2] [8,4]
[1,5] [2,2] [3,4] [4,6] [5,8] [6,3] [7,1] [8,7]
[1,5] [2,2] [3,4] [4,7] [5,3] [6,8] [7,6] [8,1]
[1,5] [2,2] [3,6] [4,1] [5,7] [6,4] [7,8] [8,3]
[1,5] [2,2] [3,8] [4,1] [5,4] [6,7] [7,3] [8,6]
[1,5] [2,3] [3,1] [4,6] [5,8] [6,2] [7,4] [8,7]
[1,5] [2,3] [3,1] [4,7] [5,2] [6,8] [7,6] [8,4]
[1,5] [2,3] [3,8] [4,4] [5,7] [6,1] [7,6] [8,2]
[1,5] [2,7] [3,1] [4,3] [5,8] [6,6] [7,4] [8,2]
[1,5] [2,7] [3,1] [4,4] [5,2] [6,8] [7,6] [8,3]
[1,5] [2,7] [3,2] [4,4] [5,8] [6,1] [7,3] [8,6]
[1,5] [2,7] [3,2] [4,6] [5,3] [6,1] [7,4] [8,8]
[1,5] [2,7] [3,2] [4,6] [5,3] [6,1] [7,8] [8,4]
[1,5] [2,7] [3,4] [4,1] [5,3] [6,8] [7,6] [8,2]
[1,5] [2,8] [3,4] [4,1] [5,3] [6,6] [7,2] [8,7]
[1,5] [2,8] [3,4] [4,1] [5,7] [6,2] [7,6] [8,3]
[1,6] [2,1] [3,5] [4,2] [5,8] [6,3] [7,7] [8,4]
[1,6] [2,2] [3,7] [4,1] [5,3] [6,5] [7,8] [8,4]
[1,6] [2,2] [3,7] [4,1] [5,4] [6,8] [7,5] [8,3]
[1,6] [2,3] [3,1] [4,7] [5,5] [6,8] [7,2] [8,4]
[1,6] [2,3] [3,1] [4,8] [5,4] [6,2] [7,7] [8,5]
[1,6] [2,3] [3,1] [4,8] [5,5] [6,2] [7,4] [8,7]
[1,6] [2,3] [3,5] [4,7] [5,1] [6,4] [7,2] [8,8]
[1,6] [2,3] [3,5] [4,8] [5,1] [6,4] [7,2] [8,7]
[1,6] [2,3] [3,7] [4,2] [5,4] [6,8] [7,1] [8,5]
[1,6] [2,3] [3,7] [4,2] [5,8] [6,5] [7,1] [8,4]
[1,6] [2,3] [3,7] [4,4] [5,1] [6,8] [7,2] [8,5]
[1,6] [2,4] [3,1] [4,5] [5,8] [6,2] [7,7] [8,3]
[1,6] [2,4] [3,2] [4,8] [5,5] [6,7] [7,1] [8,3]
[1,6] [2,4] [3,7] [4,1] [5,3] [6,5] [7,2] [8,8]
[1,6] [2,4] [3,7] [4,1] [5,8] [6,2] [7,5] [8,3]
[1,6] [2,8] [3,2] [4,4] [5,1] [6,7] [7,5] [8,3]
[1,7] [2,1] [3,3] [4,8] [5,6] [6,4] [7,2] [8,5]
[1,7] [2,2] [3,4] [4,1] [5,8] [6,5] [7,3] [8,6]
[1,7] [2,2] [3,6] [4,3] [5,1] [6,4] [7,8] [8,5]
[1,7] [2,3] [3,1] [4,6] [5,8] [6,5] [7,2] [8,4]
[1,7] [2,3] [3,8] [4,2] [5,5] [6,1] [7,6] [8,4]
[1,7] [2,4] [3,2] [4,5] [5,8] [6,1] [7,3] [8,6]
[1,7] [2,4] [3,2] [4,8] [5,6] [6,1] [7,3] [8,5]
[1,7] [2,5] [3,3] [4,1] [5,6] [6,8] [7,2] [8,4]
[1,8] [2,2] [3,4] [4,1] [5,7] [6,5] [7,3] [8,6]
[1,8] [2,2] [3,5] [4,3] [5,1] [6,7] [7,4] [8,6]
[1,8] [2,3] [3,1] [4,6] [5,2] [6,5] [7,7] [8,4]
[1,8] [2,4] [3,1] [4,3] [5,6] [6,2] [7,7] [8,5]

[1,1] [2,5] [3,8] [4,6] [5,3] [6,7] [7,2] [8,4]

[1,1] [2,6] [3,8] [4,3] [5,7] [6,4] [7,2] [8,5]

[1,1] [2,7] [3,4] [4,6] [5,8] [6,2] [7,5] [8,3]

[1,1] [2,7] [3,5] [4,8] [5,2] [6,4] [7,6] [8,3]

[1,2] [2,4] [3,6] [4,8] [5,3] [6,1] [7,7] [8,5]

[1,2] [2,5] [3,7] [4,1] [5,3] [6,8] [7,6] [8,4]

[1,2] [2,5] [3,7] [4,4] [5,1] [6,8] [7,6] [8,3]

[1,2] [2,6] [3,1] [4,7] [5,4] [6,8] [7,3] [8,5]

[1,2] [2,6] [3,8] [4,3] [5,1] [6,4] [7,7] [8,5]

[1,2] [2,7] [3,3] [4,6] [5,8] [6,5] [7,1] [8,4]

[1,2] [2,7] [3,5] [4,8] [5,1] [6,4] [7,6] [8,3]

[1,2] [2,8] [3,6] [4,1] [5,3] [6,5] [7,7] [8,4]

[1,3] [2,1] [3,7] [4,5] [5,8] [6,2] [7,4] [8,6]

[1,3] [2,5] [3,2] [4,8] [5,1] [6,7] [7,4] [8,6]

[1,3] [2,5] [3,2] [4,8] [5,6] [6,4] [7,7] [8,1]

[1,3] [2,5] [3,7] [4,1] [5,4] [6,2] [7,8] [8,6]

[1,3] [2,5] [3,8] [4,4] [5,1] [6,7] [7,2] [8,6]

[1,3] [2,6] [3,2] [4,5] [5,8] [6,1] [7,7] [8,4]

[1,3] [2,6] [3,2] [4,7] [5,1] [6,4] [7,8] [8,5]

[1,3] [2,6] [3,2] [4,7] [5,5] [6,1] [7,8] [8,4]

[1,3] [2,6] [3,4] [4,1] [5,8] [6,5] [7,7] [8,2]

[1,3] [2,6] [3,4] [4,2] [5,8] [6,5] [7,7] [8,1]

[1,3] [2,6] [3,8] [4,1] [5,4] [6,7] [7,5] [8,2]

[1,3] [2,6] [3,8] [4,1] [5,5] [6,7] [7,2] [8,4]

[1,3] [2,6] [3,8] [4,2] [5,4] [6,1] [7,7] [8,5]

[1,3] [2,7] [3,2] [4,8] [5,5] [6,1] [7,4] [8,6]

[1,3] [2,7] [3,2] [4,8] [5,6] [6,4] [7,1] [8,5]

[1,3] [2,8] [3,4] [4,7] [5,1] [6,6] [7,2] [8,5]

[1,4] [2,1] [3,5] [4,8] [5,2] [6,7] [7,3] [8,6]

[1,4] [2,1] [3,5] [4,8] [5,6] [6,3] [7,7] [8,2]

[1,4] [2,2] [3,5] [4,8] [5,6] [6,1] [7,3] [8,7]

[1,4] [2,2] [3,7] [4,3] [5,6] [6,8] [7,1] [8,5]

[1,4] [2,2] [3,7] [4,3] [5,6] [6,8] [7,5] [8,1]

[1,4] [2,2] [3,7] [4,5] [5,1] [6,8] [7,6] [8,3]

[1,4] [2,2] [3,8] [4,5] [5,7] [6,1] [7,3] [8,6]

[1,4] [2,2] [3,8] [4,6] [5,1] [6,3] [7,5] [8,7]

[1,4] [2,6] [3,1] [4,5] [5,2] [6,8] [7,3] [8,7]

[1,4] [2,6] [3,8] [4,2] [5,7] [6,1] [7,3] [8,5]

[1,4] [2,6] [3,8] [4,3] [5,1] [6,7] [7,5] [8,2]

[1,4] [2,7] [3,1] [4,8] [5,5] [6,2] [7,6] [8,3]

[1,4] [2,7] [3,3] [4,8] [5,2] [6,5] [7,1] [8,6]

[1,4] [2,7] [3,5] [4,2] [5,6] [6,1] [7,3] [8,8]

[1,4] [2,7] [3,5] [4,3] [5,1] [6,6] [7,8] [8,2]

[1,4] [2,8] [3,1] [4,3] [5,6] [6,2] [7,7] [8,5]

[1,4] [2,8] [3,1] [4,5] [5,7] [6,2] [7,6] [8,3]

[1,4] [2,8] [3,5] [4,3] [5,1] [6,7] [7,2] [8,6]

[1,5] [2,1] [3,4] [4,6] [5,8] [6,2] [7,7] [8,3]

[1,5] [2,1] [3,8] [4,4] [5,2] [6,7] [7,3] [8,6]

[1,5] [2,1] [3,8] [4,6] [5,3] [6,7] [7,2] [8,4]

[1,5] [2,2] [3,4] [4,6] [5,8] [6,3] [7,1] [8,7]

[1,5] [2,2] [3,4] [4,7] [5,3] [6,8] [7,6] [8,1]

[1,5] [2,2] [3,6] [4,1] [5,7] [6,4] [7,8] [8,3]

[1,5] [2,2] [3,8] [4,1] [5,4] [6,7] [7,3] [8,6]

[1,5] [2,3] [3,1] [4,6] [5,8] [6,2] [7,4] [8,7]

[1,5] [2,3] [3,1] [4,7] [5,2] [6,8] [7,6] [8,4]

[1,5] [2,3] [3,8] [4,4] [5,7] [6,1] [7,6] [8,2]

[1,5] [2,7] [3,1] [4,3] [5,8] [6,6] [7,4] [8,2]

[1,5] [2,7] [3,1] [4,4] [5,2] [6,8] [7,6] [8,3]

[1,5] [2,7] [3,2] [4,4] [5,8] [6,1] [7,3] [8,6]

[1,5] [2,7] [3,2] [4,6] [5,3] [6,1] [7,4] [8,8]

[1,5] [2,7] [3,2] [4,6] [5,3] [6,1] [7,8] [8,4]

[1,5] [2,7] [3,4] [4,1] [5,3] [6,8] [7,6] [8,2]

[1,5] [2,8] [3,4] [4,1] [5,3] [6,6] [7,2] [8,7]

[1,5] [2,8] [3,4] [4,1] [5,7] [6,2] [7,6] [8,3]

[1,6] [2,1] [3,5] [4,2] [5,8] [6,3] [7,7] [8,4]

[1,6] [2,2] [3,7] [4,1] [5,3] [6,5] [7,8] [8,4]

[1,6] [2,2] [3,7] [4,1] [5,4] [6,8] [7,5] [8,3]

[1,6] [2,3] [3,1] [4,7] [5,5] [6,8] [7,2] [8,4]

[1,6] [2,3] [3,1] [4,8] [5,4] [6,2] [7,7] [8,5]

[1,6] [2,3] [3,1] [4,8] [5,5] [6,2] [7,4] [8,7]

[1,6] [2,3] [3,5] [4,7] [5,1] [6,4] [7,2] [8,8]

[1,6] [2,3] [3,5] [4,8] [5,1] [6,4] [7,2] [8,7]

[1,6] [2,3] [3,7] [4,2] [5,4] [6,8] [7,1] [8,5]

[1,6] [2,3] [3,7] [4,2] [5,8] [6,5] [7,1] [8,4]

[1,6] [2,3] [3,7] [4,4] [5,1] [6,8] [7,2] [8,5]

[1,6] [2,4] [3,1] [4,5] [5,8] [6,2] [7,7] [8,3]

[1,6] [2,4] [3,2] [4,8] [5,5] [6,7] [7,1] [8,3]

[1,6] [2,4] [3,7] [4,1] [5,3] [6,5] [7,2] [8,8]

[1,6] [2,4] [3,7] [4,1] [5,8] [6,2] [7,5] [8,3]

[1,6] [2,8] [3,2] [4,4] [5,1] [6,7] [7,5] [8,3]

[1,7] [2,1] [3,3] [4,8] [5,6] [6,4] [7,2] [8,5]

[1,7] [2,2] [3,4] [4,1] [5,8] [6,5] [7,3] [8,6]

[1,7] [2,2] [3,6] [4,3] [5,1] [6,4] [7,8] [8,5]

[1,7] [2,3] [3,1] [4,6] [5,8] [6,5] [7,2] [8,4]

[1,7] [2,3] [3,8] [4,2] [5,5] [6,1] [7,6] [8,4]

[1,7] [2,4] [3,2] [4,5] [5,8] [6,1] [7,3] [8,6]

[1,7] [2,4] [3,2] [4,8] [5,6] [6,1] [7,3] [8,5]

[1,7] [2,5] [3,3] [4,1] [5,6] [6,8] [7,2] [8,4]

[1,8] [2,2] [3,4] [4,1] [5,7] [6,5] [7,3] [8,6]

[1,8] [2,2] [3,5] [4,3] [5,1] [6,7] [7,4] [8,6]

[1,8] [2,3] [3,1] [4,6] [5,2] [6,5] [7,7] [8,4]

[1,8] [2,4] [3,1] [4,3] [5,6] [6,2] [7,7] [8,5]

莫邪

知难行易

霍夫曼树和霍夫曼编码

一、定义

霍夫曼树

霍夫曼编码

二叉堆计算动态中位数

要求

分析

岁末总结

SOCKS5 协议解析

意图

代理

应用 Locust 快速上手写压测

引子

goroutine, channel 和 CSP

引子

CSP 模型

在 Node.js 中提供 gRPC 服务

引子

gRPC

WebSocket 的鉴权授权方案

引子

算法复杂度和大O表示法

概念

常见复杂度级别

八皇后问题的Julia实现

问题

实现

输出