(1)聊聊平時用到的基本數據結構，各有什么優劣，以及什么時候該用哪個數據結構； (2)聊一個自己成功的research project。著重談談這個project成功的幾個關鍵步驟; (3)一個2D矩陣，每個單元都是一個字符。相鄰字符可以連起來，這樣就可以逐漸組成 一個單詞。（一個字符可以和周圍8個方向的相鄰字符連接）。但是在一個單詞中，同 一個位置只能經過一次。打印出所有合法單詞，不重復。

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What is encapsulation?

Ans) The encapsulation is achieved by combining the methods and attribute into a class. The class acts like a container encapsulating the properties. The users are exposed mainly public methods.The idea behind is to hide how thinigs work and just exposing the requests a user can do.

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What is the different between hashtable and hashmap.

There are several differences between HashMap and Hashtable in Java:

Hashtable?is synchronized, whereas?HashMap?is not. This makes?HashMap?better for non-threaded applications, as unsynchronized Objects typically perform better than synchronized ones.

Hashtable?does not allow null keys or values.?HashMap?allows one null key and any number of?nullvalues.

One of HashMap's subclasses is?LinkedHashMap, so in the event that you'd want predictable iteration order (which is insertion order by default), you could easily swap out the?HashMap?for a?LinkedHashMap. This wouldn't be as easy if you were using?Hashtable.

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現個丑，我也當過亞馬遜的面試官，其實一天下來，真正在考你ood和coding的只有一
場，其他都是在考你解決問題的能力，應對不確定性時的能力等等，你們好歹也了解一
下公司背景啊，google關鍵字amazon leadership principles。

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Amazon leader principle
Whether you are an individual contributor or the manager of a large team, you are an Amazon leader. These are our leadership principles and every Amazonian is guided by these principles.

Customer Obsession
Leaders start with the customer and work backwards. They work vigorously to earn and keep customer trust. Although leaders pay attention to competitors, they obsess over customers.?

Ownership
Leaders are owners. They think long term and don’t sacrifice long-term value for short-term results. They act on behalf of the entire company, beyond just their own team. They never say “that’s not my job."?

Invent and Simplify
Leaders expect and require innovation and invention from their teams and always find ways to simplify. They are externally aware, look for new ideas from everywhere, and are not limited by “not invented here." As we do new things, we accept that we may be misunderstood for long periods of time.?

Are Right, A Lot
Leaders are right a lot. They have strong business judgment and good instincts.?

Hire and Develop the Best
Leaders raise the performance bar with every hire and promotion. They recognize exceptional talent, and willingly move them throughout the organization. Leaders develop leaders and take seriously their role in coaching others.?

Insist on the Highest Standards
Leaders have relentlessly high standards - many people may think these standards are unreasonably high. Leaders are continually raising the bar and driving their teams to deliver high quality products, services and processes. Leaders ensure that defects do not get sent down the line and that problems are fixed so they stay fixed.?

Think Big
Thinking small is a self-fulfilling prophecy. Leaders create and communicate a bold direction that inspires results. They think differently and look around corners for ways to serve customers.?

Bias for Action
Speed matters in business. Many decisions and actions are reversible and do not need extensive study. We value calculated risk taking.?

Frugality
We try not to spend money on things that don’t matter to customers. Frugality breeds resourcefulness, self-sufficiency, and invention. There are no extra points for headcount, budget size, or fixed expense.?

Vocally Self Critical
Leaders do not believe their or their team’s body odor smells of perfume. Leaders come forward with problems or information, even when doing so is awkward or embarrassing. Leaders benchmark themselves and their teams against the best.?

Earn Trust of Others
Leaders are sincerely open-minded, genuinely listen, and are willing to examine their strongest convictions with humility.?

Dive Deep
Leaders operate at all levels, stay connected to the details, and audit frequently. No task is beneath them.?

Have Backbone; Disagree and Commit
Leaders are obligated to respectfully challenge decisions when they disagree, even when doing so is uncomfortable or exhausting. Leaders have conviction and are tenacious. They do not compromise for the sake of social cohesion. Once a decision is determined, they commit wholly.?

Deliver Results
Leaders focus on the key inputs for their business and deliver them with the right quality and in a timely fashion. Despite setbacks, they rise to the occasion and never settle.?

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judge if a tree is balanced

What is a hash table and what would you use it for?

Write the a function that counts all pairs in an array.

Given million records, sort them out using 1K memory. Suggest the best algorithm to do this

Find all the common elements between two arrays.

Write code to check if a given tree is a Binary Search Tree (BST).

Design a hotel reservation system.

Design an elevator system using object oriented methodologies.

Given two arrays, write a method to find their intersection?

Design a Least Recently Used (LRU) cache.

What is a hash map? How could you use hash maps to find the intersection between two arrays faster?

Give an object oriented design for a restaurant reservation system.

Design a Chess game with OOD

How to design a cross-road traffic light system?

How to design Amazon’s warehouse shipping system?

Say you had a dictionary of words. How would you set it up? And what would you do if you needed to search for a word (what type of search)? About how long would it take for you to search for the word using Big O notation?

轉載于:https://www.cnblogs.com/leetcode/p/3555987.html

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