近期Amazon的coding面试真题来啦，让我们一起看看真题是什么吧。今天的真题并非传统的算法题，对于需要全面准备Amazon面试的候选人来说尤其的重要。

Amazon's latest coding interview questions are here! Let's dive into the recent questions and see what they entail. Today's questions are not your typical algorithm problems, making them especially important for candidates who need comprehensive preparation for Amazon interviews.

Q 1：从日志中统计用户词频

问题描述: 给定一个日志文件，其中包含多行用户的发言记录。每行记录了发言时间、用户名和发言内容。目标是找出词频最高的前N个用户，并按降序排列。

log.txt --------

10:00 <john> hi!

10:01 <maria> hello!

10:07 <john> can you link the design?

where john said 6 total words and maria said 1 total word.

Your goal is to present the top N users who have the highest total word count in descending order.
You need to write a function that takes an integer N and a string filepath.

You are provided a helper function, parse_log, which returns a list of usernames and word counts for each message parsed from the provided file [(‘john’, 1), (‘maria’, 1), (‘john’, 5)] for the example above.

if n = 2
return [‘john’, ‘maria’]

if n = 1
return [‘john’]

在上述示例中，john说了6个词，maria说了1个词。

解决方案:

1. 解析日志文件: 我们需要一个辅助函数 parse_log，它能够解析日志文件并返回用户名和对应的词数。
2. 统计词频: 使用字典存储每个用户的总词数。
3. 排序并返回结果: 根据词频对用户进行排序，并返回前N个用户。

代码实现思路:

• 使用文件I/O读取日志文件。
• 使用正则表达式或字符串处理函数解析每行记录。
• 使用一个字典统计每个用户的词数。
• 根据词数对字典进行排序，返回前N个用户。

Solution:

1. Parse the Log File: We need a helper function parse_log that can parse the log file and return the username and their corresponding word count.
2. Count Words: Use a dictionary to store the total word count for each user.
3. Sort and Return Results: Sort users by their word count in descending order and return the top N users.

Code Implementation Approach:

• Use file I/O to read the log file line by line.
• Use regular expressions or string manipulation functions to parse each log entry.
• Use a dictionary to count words for each user.
• Sort the dictionary by word count and return the top N users.

Q 2：软件包依赖问题

问题描述: 给定一组软件包及其依赖关系，每个依赖关系表示一个软件包需要另一个软件包成功编译后才能编译。目标是确定软件包的编译顺序。

// Hello from Carl
There is a list of packages A, B, C, D, etc and a list of dependencies:
B -> A (B depends on successful compilation of A)
X -> A, B
D -> X
E -> B, D

解决方案:

1. 构建依赖图: 使用图数据结构表示软件包和它们的依赖关系。
2. 拓扑排序: 通过拓扑排序算法确定软件包的编译顺序。

代码实现思路:

• 使用字典表示依赖图，其中键是软件包，值是该软件包依赖的其他软件包。
• 使用深度优先搜索（DFS）或广度优先搜索（BFS）实现拓扑排序，确保所有依赖的软件包都在被依赖的软件包之前编译。

Solution:

1. Build the Dependency Graph: Use a graph data structure to represent the packages and their dependencies.
2. Topological Sort: Use topological sorting algorithms to determine the compilation order of the packages.

Code Implementation Approach:

• Use a dictionary to represent the dependency graph, with keys as packages and values as the list of packages they depend on.
• Use depth-first search (DFS) or breadth-first search (BFS) to perform topological sorting, ensuring that all dependencies are resolved before compiling a package.

通过深入解析这两道Amazon面试题，求职者可以更好地理解算法设计和问题解决的核心思路，从而在实际面试中脱颖而出。希望这些详细的题解和示例代码能够帮助你在面试中取得优异成绩。

With our powerful interview assistance, candidates can effectively analyze and communicate their solutions to these interview questions. This not only demonstrates their programming abilities to the interviewer but also showcases their clear problem-solving approach and effective communication skills. These abilities are valuable not only for Amazon interviews but also for solving real-world programming problems. We wish you all the best in your interviews!

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