Numadic Interview Questions and Answers

Diameter of a binary tree is the longest path between any two leaf nodes.

• Calculate the height of left and right subtrees recursively.

• Calculate the diameter recursively using the formula max(left_height + right_height + 1, max(left_diameter, right_diameter)).

• Return the maximum diameter.

To find interchanged terms from an AP series

• Identify the common difference between terms

• Swap the positions of adjacent terms

• Check if the new series is also an AP

• Repeat until no more interchanged terms can be found

Database indexing is a technique to improve the performance of database queries.

• Indexing creates a data structure that allows for faster retrieval of data.

• Indexes are created on one or more columns of a table.

• Queries that use indexed columns can be executed faster.

• Indexes can be clustered or non-clustered.

• Clustered indexes determine the physical order of data in a table.

• Non-clustered indexes create a separate structure...read more

Optimizing PHP and MySQL queries involves using indexes, optimizing queries, and reducing data transfer.

• Use indexes to speed up data retrieval

• Optimize queries by avoiding unnecessary joins and subqueries

• Reduce data transfer by selecting only necessary columns

• Use caching to avoid repetitive queries

• Avoid using SELECT *

• Use EXPLAIN to analyze query performance