How do I approach Coding & Algorithms interview questions?

Coding & Algorithms questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master coding & algorithms interviews.

What difficulty level is this interview question?

This is a medium difficulty Coding & Algorithms question, commonly asked during Technical Screen rounds at Meta.

What role is this question designed for?

This question is commonly asked for Software Engineer candidates at Meta during technical interviews.

Solve Three Coding Interview Problems | Meta Interview Question

Q: Solve Three Coding Interview Problems

This set of tasks evaluates proficiency in data structures and algorithms, covering tree traversal and lowest common ancestor reasoning, interval merging and overlap resolution, and combinatorial subset selection under uniqueness constraints.

The interview included three coding tasks:

Common ancestor in an N-ary tree
You are given the root of an N-ary tree and two target nodes. Determine whether the two nodes share a common ancestor, and if they do, return their lowest common ancestor. If either node does not exist in the tree, return null .
Merge two sorted interval lists
You are given two sorted lists of non-overlapping intervals:
- intervals1 = [[1, 2], [3, 4]]
- intervals2 = [[1, 3], [7, 8], [9, 10]]
Merge all intervals from both lists into one sorted list of non-overlapping intervals. For the example above, the output should be: [[1, 4], [7, 8], [9, 10]]
Maximum-length subset of words with unique letters
You are given a list of lowercase words. Choose a subset of words such that no letter appears more than once across the entire chosen subset. Return the maximum possible total number of characters in the chosen subset.

For all three tasks, explain the algorithm and analyze time and space complexity.

The interview included three coding tasks:

Common ancestor in an N-ary tree
You are given the root of an N-ary tree and two target nodes. Determine whether the two nodes share a common ancestor, and if they do, return their lowest common ancestor. If either node does not exist in the tree, return null .
Merge two sorted interval lists
You are given two sorted lists of non-overlapping intervals:
- intervals1 = [[1, 2], [3, 4]]
- intervals2 = [[1, 3], [7, 8], [9, 10]]
Merge all intervals from both lists into one sorted list of non-overlapping intervals. For the example above, the output should be: [[1, 4], [7, 8], [9, 10]]
Maximum-length subset of words with unique letters
You are given a list of lowercase words. Choose a subset of words such that no letter appears more than once across the entire chosen subset. Return the maximum possible total number of characters in the chosen subset.

For all three tasks, explain the algorithm and analyze time and space complexity.

Solve Three Coding Interview Problems

Quick Overview

Submit Your Answer

Solve Three Coding Interview Problems

Quick Overview

Submit Your Answer