Dunzo Senior Software Engineer Interview Questions and Answers

Answering how to remove a character sequence with a particular number from a string.

• Identify the character sequence to be removed

• Use string manipulation functions to remove the sequence

• Repeat until all instances of the sequence are removed

Find the second best player among n players.

• Sort the players based on their scores and pick the second highest score.

• If scores are not available, find the second highest rank or position.

• If there are ties for first place, the second best player may be the third or fourth best player.

• If there are ties for second place, there may not be a clear second best player.

Transpose of a square matrix

• Iterate through each row and column of the matrix

• Swap the elements at (i,j) and (j,i) positions

• Return the transposed matrix

Rotate a 2D matrix 90' anticlockwise

• Transpose the matrix

• Reverse each row of the transposed matrix

• Alternatively, swap elements in each row with their corresponding elements in the opposite row

• Time complexity: O(n^2), Space complexity: O(1)

Streams in Java are a sequence of elements that can be processed in parallel or sequentially.

• Streams are used to perform operations on collections of data.

• They can be used to filter, map, reduce, and sort data.

• Streams can be processed in parallel to improve performance.

• Examples include using streams to filter a list of names or map a list of numbers to their squares.

Lambda expression is a concise way to represent anonymous functions in Java.

• Lambda expressions were introduced in Java 8.

• They are used to implement functional interfaces.

• They reduce the amount of boilerplate code needed for anonymous classes.

• Syntax: (parameters) -> expression or (parameters) -> { statements; }

• Example: (x, y) -> x + y or (x, y) -> { return x + y; }

Indexing in database is a way to optimize search queries by creating a data structure that allows for faster retrieval of data.

• Indexing involves creating a separate table that contains the indexed columns and their corresponding row locations.

• Indexes can be created on one or multiple columns.

• Indexes can be clustered or non-clustered.

• Examples of indexing include primary keys, foreign keys, and unique constraints.

Indexing can lead to increased storage requirements and slower write performance.

• Indexing can increase the size of the database as additional data structures are created to support the index.

• Indexes can slow down write operations as the database must update both the data and the index.

• Indexes can become fragmented over time, leading to decreased performance.

• Indexes can also lead to increased memory usage and CPU overhe...read more