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How to Solve Detect Cycles in 2D Grid Problem
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Start Free for WindowsMedium#1559
LeetCode ProblemDetect Cycles in 2D Grid
Given a 2D array of characters grid of size m x n, you need to find if there exists any cycle consisting of the same value in grid. A cycle is a path of length 4 or more in the grid that starts and ends at the same cell. From a given cell, you can move to one of the cells adjacent to it - in one of the four directions (up, down, left, or right), if it has the same value of the current cell. Also, you cannot move to the cell that you visited in your last move. For example, the cycle (1, 1) -> (1, 2) -> (1, 1) is invalid because from (1, 2) we visited (1, 1) which was the last visited cell. Return true if any cycle of the same value exists in grid, otherwise, return false.
ArrayDepth-First SearchBreadth-First SearchUnion FindMatrix
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Problem Breakdown
Understanding the Detect Cycles in 2D Grid Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
Given a 2D array of characters grid of size m x n, you need to find if there exists any cycle consisting of the same value in grid. A cycle is a path of length 4 or more in the grid that starts and ends at the same cell. From a given cell, you can move to one of the cells adjacent to it - in one of the four directions (up, down, left, or right), if it has the same value of the current cell. Also, you cannot move to the cell that you visited in your last move. For example, the cycle (1, 1) -> (1, 2) -> (1, 1) is invalid because from (1, 2) we visited (1, 1) which was the last visited cell. Return true if any cycle of the same value exists in grid, otherwise, return false.
MediumProblem #1559
LeetCodeDetect Cycles in 2D Grid
Related Topics
ArrayDepth-First SearchBreadth-First SearchUnion FindMatrix
How Phantom Code Helps
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Examples
# Example 1
Input
grid = [["a","a","a","a"],["a","b","b","a"],["a","b","b","a"],["a","a","a","a"]]
Output
true
# Example 2
Input
grid = [["c","c","c","a"],["c","d","c","c"],["c","c","e","c"],["f","c","c","c"]]
Output
true
# Example 3
Input
grid = [["a","b","b"],["b","z","b"],["b","b","a"]]
Output
false
Constraints
m == grid.length
n == grid[i].length
1 <= m, n <= 500
grid consists only of lowercase English letters.
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Solve Detect Cycles in 2D Grid — Given a 2D array of characters grid of size m x n, you need to find if there exi...
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Frequently Asked Questions
Common questions about solving Detect Cycles in 2D Grid and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Detect Cycles in 2D Grid 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 Detect Cycles in 2D Grid?
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 Detect Cycles in 2D Grid?
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.
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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 Detect Cycles in 2D Grid 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 Detect Cycles in 2D Grid during live interviews?
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How does Phantom Code help when I'm struggling with Detect Cycles in 2D Grid 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 Detect Cycles in 2D Grid interviews?
Yes. Phantom Code works with all major coding platforms including LeetCode, HackerRank, CodeSignal, CoderPad, HackerEarth, and any browser-based coding environment.
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