Phantom CodePhantom Code
Proof
NEW
Earn with UsHelpBlogsFAQ
Proof
NEW
Earn with UsHelp CenterBlogsFAQMy PromptsFeedbackSubscribe
Phantom CodePhantom Code
Proof
NEW
Earn with UsHelpBlogsFAQ
Proof
NEW
Earn with UsHelp CenterBlogsFAQMy PromptsFeedbackSubscribe
HomeLeetCode ProblemsIsland Perimeter
Used by thousands of developers who passed their interviews

How to Solve Island Perimeter Problem

Master the Island Perimeter LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.

Phantom Code generates complete solutions and debugging hints that you can use while explaining your approach, so you stay calm and in control.

undetectable
real-time
works on major platforms
WindowsStart Free for Windows
Easy#463
LeetCode Problem

Island Perimeter

You are given row x col grid representing a map where grid[i][j] = 1 represents land and grid[i][j] = 0 represents water. Grid cells are connected horizontally/vertically (not diagonally). The grid is completely surrounded by water, and there is exactly one island (i.e., one or more connected land cells). The island doesn't have "lakes", meaning the water inside isn't connected to the water around the island. One cell is a square with side length 1. The grid is rectangular, width and height don't exceed 100. Determine the perimeter of the island.

ArrayDepth-First SearchBreadth-First SearchMatrix

Phantom Code will help you solve this problem in real-time during your interview

Get instant solutions, explanations, and code generation
Problem Breakdown

Understanding the Island Perimeter Problem

Let's break down this LeetCode problem and understand what makes it challenging in interview settings.

Problem Statement

You are given row x col grid representing a map where grid[i][j] = 1 represents land and grid[i][j] = 0 represents water. Grid cells are connected horizontally/vertically (not diagonally). The grid is completely surrounded by water, and there is exactly one island (i.e., one or more connected land cells). The island doesn't have "lakes", meaning the water inside isn't connected to the water around the island. One cell is a square with side length 1. The grid is rectangular, width and height don't exceed 100. Determine the perimeter of the island.

EasyProblem #463
LeetCode

Island Perimeter

Related Topics

ArrayDepth-First SearchBreadth-First SearchMatrix

How Phantom Code Helps

Get real-time assistance for Island Perimeter problems during coding interviews. Phantom Code provides instant solutions and explanations.

Examples

# Example 1

Input
grid = [[0,1,0,0],[1,1,1,0],[0,1,0,0],[1,1,0,0]]
Output
16

# Example 2

Input
grid = [[1]]
Output
4

# Example 3

Input
grid = [[1,0]]
Output
4

Constraints

row == grid.length
col == grid[i].length
1 <= row, col <= 100
grid[i][j] is 0 or 1.
There is exactly one island in grid.

How Phantom Code Helps with LeetCode Problems

Reinforce undetectability, platform compatibility, and real-time assistance to remove any doubt.

1000+
developers use Phantom Code
and growing every day
95%
success rate
of users pass their interviews
100%
undetectable
native desktop architecture
Real-time
assistance
instant solutions during interviews

See Phantom Code in Action

Watch how Phantom Code helps solve LeetCode problems during live interviews

Phantom Code
Start Interview
⌘I
Online Round
⌘O
Hide⌘B
Interview
Listening
Think

Solve Island Perimeter — You are given row x col grid representing a map where grid[i][j] = 1 represents ...

Here's the optimal approach using Array:

def solve(input):
# Optimal O(n) solution
return result

Time: O(n)  |  Space: O(n)

Start Over ⌘G
Think & Crack ⌘↵

Undetectability Checklist

Run compatibility test before interviews
Use recommended Zoom version settings
Enable advanced screen capture options
Verify native desktop architecture
Test with screen recording software

Platform Compatibility

Zoom
Supported
Google Meet
Supported
HackerRank
Supported
CodeSignal
Supported
CoderPad
Supported
Teams
Supported

User results and traction

Thousands of developers use Phantom Code. Social proof signals that this approach helps real candidates land offers across a range of companies.

Undetectability and technical details

Our native desktop architecture avoids common detection vectors used by browser extensions. We provide a clear checklist so you can run basic checks and confirm the app will be invisible.

Platform compatibility and limitations

We work with Zoom, HackerRank, CodeSignal, CoderPad and other web-based platforms. Check the compatibility note and request a browser link if a specific desktop app is unsupported.

Frequently Asked Questions

Common questions about solving Island Perimeter and using Phantom Code during coding interviews.

How does Phantom Code help me solve coding problems like Island Perimeter during interviews?
Phantom Code generates complete solutions instantly with proper complexity analysis, letting you focus on explaining your approach and demonstrating problem-solving skills rather than getting stuck on implementation details during high-pressure situations.
What if the interviewer asks follow-up questions or modifications to problems like Island Perimeter?
Phantom Code adapts in real-time. Screenshot the modified problem or use audio mode to capture the interviewer's follow-up, and get an updated solution within seconds — including edge cases and optimizations.
Can Phantom Code help me communicate my solution for problems like Island Perimeter?
Yes. Phantom Code provides step-by-step approach explanations with 3 progressive thoughts, so you can walk through your solution naturally. It also provides time and space complexity analysis to discuss trade-offs.
How does Phantom Code assist with different programming languages for Island Perimeter type problems?
Phantom Code supports 11 programming languages including Python, Java, C++, JavaScript, TypeScript, Go, Rust, Ruby, Swift, Kotlin, and C#. Set your preferred language and get idiomatic solutions.
What coding mistakes does Phantom Code help me avoid during Island Perimeter interviews?
Phantom Code catches common mistakes like off-by-one errors, missing edge cases, incorrect base conditions, and suboptimal approaches. It provides clean, well-structured code that handles all edge cases.
Is Phantom Code detectable when solving problems like Island Perimeter during live interviews?
No. Phantom Code runs as an invisible desktop overlay that doesn't appear in screen shares, recordings, or proctoring software. It works with Zoom, HackerRank, CodeSignal, CoderPad, and all major platforms.
How does Phantom Code help when I'm struggling with Island Perimeter style questions under pressure?
The AI provides structured guidance: first the approach (what algorithm/data structure to use and why), then the implementation with clean code, and finally complexity analysis. This helps you think clearly even under pressure.
Does Phantom Code work for the coding platforms used in Island Perimeter interviews?
Yes. Phantom Code works with all major coding platforms including LeetCode, HackerRank, CodeSignal, CoderPad, HackerEarth, and any browser-based coding environment.
Phantom Code

₹999/month. Zero Detection Cases.

The only AI interview tool with an undetectable desktop overlay, real-time audio listening, and personalized AI responses.

WindowsStart Free for Windows
Phantom CodePhantom Code
Phantom Code is an undetectable desktop application to help you pass your Leetcode interviews.
All systems online

Legal

Refund PolicyTerms of ServiceCancellation PolicyPrivacy Policy

Pages

Contact SupportHelp CenterFAQBlogPricingFeedbackLeetcode ProblemsLoginCreate Account

Compare

Interview Coder AlternativeFinal Round AI AlternativeUltraCode AI AlternativeParakeet AI AlternativeAI Apply AlternativeCoderRank AlternativeInterviewing.io AlternativeShadeCoder Alternative

Resources

Salary GuideResume Templates

Interview Types

Coding InterviewSystem Design InterviewDSA InterviewLeetCode InterviewAlgorithms InterviewData Structure InterviewSQL InterviewOnline Assessment

© 2026 Phantom Code. All rights reserved.