LeetCopilot is a Chrome extension that lives right inside LeetCode. It understands your code, tests, and errors to give step-by-step guidance — helping you progress without spoilers.

Is it really free to use?

Yes. LeetCopilot is completely free during early access — no hidden fees, no trial limits. You get the full product, no strings attached.

Do I need to create an account?

Yes. You can sign in with Google, GitHub, or email. This lets you securely sync chats, notes, and flashcards across devices.

How does it help me study smarter?

Study Mode turns every solved problem into structured notes, extracts complexity analysis, and creates flashcards — so you can review weaknesses without extra manual work.

Can it help me prepare for interviews?

Yes. Interview Mode simulates a real interviewer, asks follow-up questions, and gives feedback on clarity, correctness, and speed — so you know exactly what to improve.

Which browsers are supported?

LeetCopilot works on Chrome and Chromium browsers like Edge and Brave. Firefox and others are planned after early access.

AI-Powered LeetCode Assistant

Master LeetCode
Without the Struggle

Your intelligent copilot for coding interviews. Get real-time hints, visualize algorithms, and track your progress—directly in your browser.

Also compatible with Edge, Brave, and Opera

Chat

Get a hint to move forward...

Learning

Everything you need to master LeetCode

AI-powered tools designed to accelerate your DS&A learning journey on LeetCode

Chat Mode

Get unstuck with step-by-step hints and context-aware feedback. Highlight any part of a problem and receive clear guidance inline, without spoilers.

Study Mode

Turn solved problems into structured notes, quizzes, and flashcards. Build a growing library of insights you can revisit anytime.

Interview Mode

Practice adaptive mock interviews that probe your reasoning, not just final answers. Get detailed feedback grounded in your own code and results.

Smart Context

LeetCopilot understands your code, test cases, and submission history. Every suggestion is precision-tailored to your workspace — no generic answers.

Agentic Intelligence

Go beyond advice with tools that act on your behalf. Run code, generate edge-case tests, and visualize algorithms in real time for deeper understanding.

Powerful Models

Powered by cutting-edge AI models tuned for DS&A challenges. Get accurate, efficient, and developer-friendly assistance built for coding practice.

Chat Mode

Get unstuck,
stay in flow

Don't let a difficult problem break your momentum. LeetCopilot provides intelligent assistance that guides you to the solution without giving it away.

💡
Guided hints, no spoilers
Step-by-step nudges that build your reasoning.
🎯
Context-aware feedback
Uses your code, tests, and errors for precise help.
⚡
Instant selection
Highlight on LeetCode to ask instantly — no more tab-switching.

Chat

Ask about your code...

Hints

Agentic Intelligence

Tools that act,
not just suggest

Go beyond simple chat. LeetCopilot comes with powerful tools that can execute code, visualize data structures, and more.

🧪
Validate instantly
Run your code on sample or batched edge cases to uncover hidden bugs.
👁️
See it clearly
Step through code execution and explore data structures with visualizations.
📚
Go beyond the page
Surface relevant videos and capture quick notes to build your knowledge base.

Chat

Ask about your code...

Hints

Study Mode

Turn practice
into mastery

Stop solving problems in isolation. Build a personal knowledge base that grows with every problem you solve.

📝
Capture insights automatically
Generate notes with approaches, complexity, and key takeaways.
🧠
Reinforce smarter
Personalized flashcards and quizzes based on your mistakes.
🗺️
Plan your journey
Generate a custom LeetCode study roadmap tailored to your goals.

Study

Container With Most Water: Study Note

1. Problem Summary

Given an array of heights, find two lines that form a container holding the most water
Problem type: Array, Two Pointers, Greedy
Difficulty level: Medium
Key constraints:
- Input size: up to 10⁵ elements
- Element values: up to 10⁴
- Need O(n) time solution due to input size

2. Approaches & Strategies

Brute Force: Check all pairs of lines
- Time: O(n²), Space: O(1)
- Inefficient for large inputs
Two Pointer Technique (Optimal):
- Start with widest container (left=0, right=n-1)
- Move pointer at shorter line inward
- Justification: Moving taller line inward can only decrease area
- Time: O(n), Space: O(1)
Key Insight: Area = min(height[left], height[right]) × (right - left)

3. My Solution & Code

Used optimal two-pointer approach
Strategy: Start with maximum width, greedily move shorter pointer
More efficient than brute force by eliminating impossible candidates

from typing import List

class Solution:
    """
    Classic optimal solution:
    start with the outermost pair and move the pointer
    at the shorter line inward.  The area can only
    get smaller when the width shrinks, so we can safely
    discard the shorter line.
    """
    def maxArea(self, height: List[int]) -> int:
        left, right = 0, len(height) - 1
        max_water = 0

        while left < right:
            width = right - left
            h = min(height[left], height[right])
            max_water = max(max_water, width * h)

            # Move the pointer that is at the shorter line
            if height[left] < height[right]:
                left += 1
            else:
                right -= 1

        return max_water

4. Time & Space Complexity

Final Solution: O(n) time, O(1) space
Brute Force Alternative: O(n²) time, O(1) space
Trade-off: Linear time vs quadratic time, same space
Justification: Each element visited at most once

5. Mistakes & Insights

Early submissions (2022): Same correct logic but slower execution (700-1600ms)
Recent submission (2025): Same logic but faster (91ms, 78% percentile)
Improvement: Code structure and variable naming became cleaner
Key Insight: Moving the shorter line is safe because:
- Width always decreases
- Height cannot exceed shorter line
- Keeping shorter line cannot improve area
Debugging history: Initially questioned brute force vs optimal approach
Learning: Recognized pattern of two-pointer optimization for array problems

6. What's Next

Focus Areas:
- Two-pointer technique variations
- Greedy algorithm justification
Recommended Problems:
- Trapping Rain Water (Hard): Extends container concept to multiple bars
- 3Sum (Medium): Uses two-pointer technique for triplet search
- Two Sum II - Input Array Is Sorted (Medium): Basic two-pointer sorted array search

Interview Mode

Simulate interviews,
build confidence

Don't let the first time you explain your code be in the actual interview. Practice with an AI that pushes you to communicate clearly.

🎤
Think on your feet
Adaptive mock interviews that test reasoning, not just answers.
👥
Experience real dynamics
Practice with diverse interviewer personalities and styles.
📊
Improve with clarity
Get detailed feedback, score breakdowns, and concrete suggestions.

Live

01:40

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Loved by Top Engineers

Join thousands of developers who have leveled up their coding skills and landed their dream jobs with LeetCopilot.

Honestly, I used to just memorize solutions and move on. LeetCopilot's hints actually made me think through the problem properly. Now I understand why certain approaches work, not just that they do.

Sarah Chen

Software Engineer at Google

I was getting destroyed in interviews because I couldn't explain my thinking. The notes feature helped me organize my approach, and now I actually know what I'm talking about when I code.

Alex Rodriguez

CS Student at Stanford

The interview practice mode is legit. I used to freeze up when explaining code, but practicing with it made me way more comfortable. Got the offer at my dream company!

Priya Patel

Frontend Developer at Airbnb

Best part? It actually reads my code and sees what's failing. Instead of generic advice, it points to the exact issue. Saves me from opening 10 Stack Overflow tabs.

James Wilson

SDE II at Amazon

I thought I was good at explaining my approach until Interview Mode grilled me. The questions it asks are brutal, but that's exactly what I needed. Real interviews felt easy after this.

Michael Chang

Senior Engineer at Meta

Honestly, I used to just memorize solutions and move on. LeetCopilot's hints actually made me think through the problem properly. Now I understand why certain approaches work, not just that they do.

Sarah Chen

Software Engineer at Google

I was getting destroyed in interviews because I couldn't explain my thinking. The notes feature helped me organize my approach, and now I actually know what I'm talking about when I code.

Alex Rodriguez

CS Student at Stanford

The interview practice mode is legit. I used to freeze up when explaining code, but practicing with it made me way more comfortable. Got the offer at my dream company!

Priya Patel

Frontend Developer at Airbnb

Best part? It actually reads my code and sees what's failing. Instead of generic advice, it points to the exact issue. Saves me from opening 10 Stack Overflow tabs.

James Wilson

SDE II at Amazon

I thought I was good at explaining my approach until Interview Mode grilled me. The questions it asks are brutal, but that's exactly what I needed. Real interviews felt easy after this.

Michael Chang

Senior Engineer at Meta

Honestly, I used to just memorize solutions and move on. LeetCopilot's hints actually made me think through the problem properly. Now I understand why certain approaches work, not just that they do.

Sarah Chen

Software Engineer at Google

I was getting destroyed in interviews because I couldn't explain my thinking. The notes feature helped me organize my approach, and now I actually know what I'm talking about when I code.

Alex Rodriguez

CS Student at Stanford

The interview practice mode is legit. I used to freeze up when explaining code, but practicing with it made me way more comfortable. Got the offer at my dream company!

Priya Patel

Frontend Developer at Airbnb

Best part? It actually reads my code and sees what's failing. Instead of generic advice, it points to the exact issue. Saves me from opening 10 Stack Overflow tabs.

James Wilson

SDE II at Amazon

I thought I was good at explaining my approach until Interview Mode grilled me. The questions it asks are brutal, but that's exactly what I needed. Real interviews felt easy after this.

Michael Chang

Senior Engineer at Meta

Honestly, I used to just memorize solutions and move on. LeetCopilot's hints actually made me think through the problem properly. Now I understand why certain approaches work, not just that they do.

Sarah Chen

Software Engineer at Google

I was getting destroyed in interviews because I couldn't explain my thinking. The notes feature helped me organize my approach, and now I actually know what I'm talking about when I code.

Alex Rodriguez

CS Student at Stanford

The interview practice mode is legit. I used to freeze up when explaining code, but practicing with it made me way more comfortable. Got the offer at my dream company!

Priya Patel

Frontend Developer at Airbnb

Best part? It actually reads my code and sees what's failing. Instead of generic advice, it points to the exact issue. Saves me from opening 10 Stack Overflow tabs.

James Wilson

SDE II at Amazon

I thought I was good at explaining my approach until Interview Mode grilled me. The questions it asks are brutal, but that's exactly what I needed. Real interviews felt easy after this.

Michael Chang

Senior Engineer at Meta

Being able to highlight text and ask questions is so convenient. The execution traces showed me exactly where my logic broke down. Wish I had this in college.

Emma Davis

Engineer at Netflix

Sliding window finally makes sense after seeing it visualized. The step-by-step traces are a lifesaver for debugging. I can actually see what my code is doing instead of guessing.

David Kim

iOS Developer at Apple

I used to solve problems and forget everything. Now Study Mode auto-generates notes and flashcards that I actually use. My retention improved so much, and I'm not just cramming anymore.

Lisa Wang

Lisa Wang

CS Student at UCSD

Robert Taylor

Backend Engineer at Uber

Everything's right there on the page, so I don't lose context switching tabs. The hints guide you without giving it away, and the quizzes help reinforce concepts. Really solid workflow.

Jennifer Wu

Full Stack at Stripe

Land your dream job

From internships to senior roles, LeetCopilot helps users secure positions across major tech companies and startups.

Apple

iOS Engineer

Microsoft

Software Engineer

Codepen

Frontend Engineer

Frontend Engineer

Amazon

SDE II

Tesla

ML Engineer

Airbnb

Full Stack Engineer

Google

Applied Scientist

Applied Scientist

Meta

Software Engineer

Netflix

Backend Engineer

Uber

Data Engineer

Stripe

Security Engineer

$0/month

Step-by-step AI hints
Auto-generated study notes
Personalized quizzes and flashcards
Realistic mock interviews
Smart context awareness
Agentic AI tools
Powerful coding-optimized AI models
Custom study roadmap

How to Get Started

Set up LeetCopilot in just a few simple steps

Install the Extension

Add LeetCopilot from Chrome Web Store to your browser in seconds. Compatible with Chrome, Edge, Brave, and Opera.

Open a LeetCode Problem

Navigate to any problem on LeetCode. Launch LeetCopilot and sign in with Google, GitHub, or email. LeetCopilot automatically detects the problem and is ready to help.

Start Chatting

Ask any question, highlight any code snippet or text on LeetCode page to get instant hints, explanations, and step-by-step guidance tailored to your progress.

Frequently Asked Questions

Everything you need to know about LeetCopilot

Still have questions? Contact our support team

Ready to ace your
coding interviews?

Join thousands of developers mastering LeetCode with AI-powered guidance

Also compatible with Edge, Brave, and Opera

Master LeetCodeWithout the Struggle

Everything you need to master LeetCode

Chat Mode

Study Mode

Interview Mode

Smart Context

Agentic Intelligence

Powerful Models

Get unstuck, stay in flow

Tools that act, not just suggest

Turn practice into mastery

Container With Most Water: Study Note

1. Problem Summary

2. Approaches & Strategies

3. My Solution & Code

4. Time & Space Complexity

5. Mistakes & Insights

6. What's Next

Simulate interviews, build confidence

Loved by Top Engineers

Sarah Chen

Alex Rodriguez

Priya Patel

James Wilson

Michael Chang

Sarah Chen

Alex Rodriguez

Priya Patel

James Wilson

Michael Chang

Sarah Chen

Alex Rodriguez

Priya Patel

James Wilson

Michael Chang

Sarah Chen

Alex Rodriguez

Priya Patel

James Wilson

Michael Chang

Emma Davis

David Kim

Lisa Wang

Robert Taylor

Jennifer Wu

Emma Davis

David Kim

Lisa Wang

Robert Taylor

Jennifer Wu

Emma Davis

David Kim

Lisa Wang

Robert Taylor

Jennifer Wu

Emma Davis

David Kim

Lisa Wang

Robert Taylor

Jennifer Wu

Land your dream job

Apple

Microsoft

Codepen

Amazon

Apple

Microsoft

Codepen

Amazon

Apple

Microsoft

Codepen

Amazon

Apple

Microsoft

Codepen

Amazon

Tesla

Airbnb

Google

Master LeetCode
Without the Struggle

Get unstuck,
stay in flow

Tools that act,
not just suggest

Turn practice
into mastery

Simulate interviews,
build confidence

Ready to ace your
coding interviews?