Count median in binary tree

Last updated: April 4, 2026

Quick Overview

Count the number of shortest distance in the given graph.

Twitter/X

Coding & Algorithms

Machine Learning Engineer

Twitter/X

April 4, 2026

Machine Learning Engineer

Onsite

Coding & Algorithms

Medium

2,766 solved

Count the number of shortest distance in the given graph.

This coding problem is frequently asked during Onsite at Twitter/X. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Twitter/X expects candidates to write production-quality code, not just solve the puzzle.

What the Interviewer Expects

Recognize the underlying problem pattern (sliding window, two pointers, BFS/DFS, etc.)
Discuss multiple approaches and trade-offs before coding
Implement an optimal solution with clean, production-quality code
Handle all edge cases including boundary conditions and invalid input
Optimize both time and space complexity with clear justification
Test your solution systematically with well-chosen examples

Key Topics to Cover

Binary search and divide and conquer

Sorting and searching

Data structure selection and trade-offs

Edge cases and input validation

Hash maps and frequency counting

How to Approach This

Clarify input constraints and edge cases before writing code.
Walk through your approach verbally and confirm with the interviewer before coding.
Start with a brute force solution, then optimize. Mention time and space complexity.
Test your solution with examples, including edge cases like empty input or duplicates.
Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.

Possible Follow-up Questions

How would your solution change if the input was sorted?
Can you optimize the space complexity of your solution?
Can you solve this in a single pass?

Sharpen Your Skills on Codemia

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Practice DSA Problems

Sample Answer

Problem Analysis

Start by understanding the input/output format and constraints. Identify the core problem pattern. Ask clarifying questions: Is the input sorted? Can ...

Brute Force Approach

Always start with the simplest correct solution, even if it's not optimal. This shows you can solve the problem and gives you a baseline to optimize f...

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Twitter/X Machine Learning Engineer Interview Guide

Interview process, tips, and preparation timeline