Top 10 Must-Have Coding Questions to Crack the Amazon Interview


by Sayantani Sanyal


March 22, 2022

It is crucial for any Amazon aspirant to prepare crucial coding questions in advance

Coding and programming have become one of the most popular tech careers, making huge strides among tech aspirants. But to gain positions in leading companies like Amazon, Microsoft, IBM, Google and others, these aspirants should be aware of essential algorithms and methods and should have a good command of programming languages ​​such as Java, especially if they are applying for programming jobs. Companies like Amazon have a pretty strict screening and hiring process. Amazon is also considered one of the toughest tech giants to get past. It organizes online coding tests, and aspirants are required to prepare well for them coding questions to pass the Amazon interview. These top coding questions differ in moderation depending on the candidates’ previous professional or educational experience and qualifications. In this article, we have listed the top coding questions and answers that Interview with Amazon candidates should respond and prepare.

How to find the first non-repeated character of a word?

A function must be written that accepts strings and returns the first non-repeating characters. In order to write code that will return the first non-repeated letters, we can use the LinkedHashMap to store the number of characters. This HashMap follows the insertion order and the characters are initialized to the same position as in the string. The fraudulent string should be iterated over using LinkedHashMap to choose the required entry with the value 1.

Explain the meaning of a doubly linked list.

Doubly linked lists are classified as a special type of linked list in which traversal of data items can be done in both directions. This is made possible by the presence of two links in each node, one that connects the next node and another that connects to the previous one.

What are dynamic data structures?

Dynamic data structures have the characteristic of growing and contracting as a program executes. It provides a very flexible method of data manipulation as it adjusts according to the size of the data to be manipulated.

How does variable declaration affect memory?

The amount of memory that should be reserved or allocated depends on the type of data stored in this variable. For example, if a variable is declared of ‘integer type’, then 32 bits of memory storage will be reserved for that particular variable.

How to remove given character from String in Java?

One of the easiest solutions to this problem is to iterate over String converting it to an array of characters and checking if the current character is the same as a given character to be removed or not, or professionals can also add to the StringBuilder. At the end of the iteration, they will have a StringBuilder with all the characters except the one that is requested to be removed. Just convert this StringBuilder to String, and they’ll have their solution ready.

Which sorting algorithm do you think is the best?

There are many sorting algorithms including bubble sort, quick sort, bubble sort, merge sort, radix sort, etc. But no algorithm can be said to be the best or the fastest because each has been designed for a specific type of data structure where it performs best.

What is a Deque?

A deque is a double-ended queue. It is a structure in which elements can be inserted or removed at either end.

What do you mean by recursion?

Recursion refers to a function calling itself based on a termination condition. It uses LIFO and therefore uses the stack data structure.

How are you going to reverse words in a target sentence without using library methods?

To effectively reverse a sentence, we need to use regular expressions in Java to split the given strings into spaces, and then apply the reverse() method of the Collections utility class. Once we split the strings using regex ‘s’ an array of words will be returned accordingly. This also supports splitting words using multiple spaces. As soon as the array is returned, coders can choose to create ArrayLists from those arrays followed by the use of Collections. reverse() method. This reverses the ArrayLists and each word will be reset in reverse order.

What is a linked list?

Like an array, a linked list refers to a linear data structure in which elements are not necessarily stored contiguously. It is basically a sequence of nodes, each node points to the next node forming a chain-like structure.

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