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How to Solve Battleships in a Board Problem
Master the Battleships in a Board LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsMedium#419
LeetCode ProblemBattleships in a Board
Given an m x n matrix board where each cell is a battleship 'X' or empty '.', return the number of the battleships on board. Battleships can only be placed horizontally or vertically on board. In other words, they can only be made of the shape 1 x k (1 row, k columns) or k x 1 (k rows, 1 column), where k can be of any size. At least one horizontal or vertical cell separates between two battleships (i.e., there are no adjacent battleships). Example 1: Example 2: Constraints: Follow up: Could you do it in one-pass, using only O(1) extra memory and without modifying the values board?
ArrayDepth-First SearchMatrix
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Problem Breakdown
Understanding the Battleships in a Board Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
Given an m x n matrix board where each cell is a battleship 'X' or empty '.', return the number of the battleships on board. Battleships can only be placed horizontally or vertically on board. In other words, they can only be made of the shape 1 x k (1 row, k columns) or k x 1 (k rows, 1 column), where k can be of any size. At least one horizontal or vertical cell separates between two battleships (i.e., there are no adjacent battleships). Example 1: Example 2: Constraints: Follow up: Could you do it in one-pass, using only O(1) extra memory and without modifying the values board?
MediumProblem #419
LeetCodeBattleships in a Board
Related Topics
ArrayDepth-First SearchMatrix
How Phantom Code Helps
Get real-time assistance for Battleships in a Board problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
board = [["X",".",".","X"],[".",".",".","X"],[".",".",".","X"]]
Output
2
# Example 2
Input
board = [["."]]
Output
0
Constraints
m == board.length
n == board[i].length
1 <= m, n <= 200
board[i][j] is either '.' or 'X'.
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Solve Battleships in a Board — Given an m x n matrix board where each cell is a battleship 'X' or empty '.', re...
Here's the optimal approach using Array:
def solve(input):
# Optimal O(n) solution
return result
Time: O(n) | Space: O(n)
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Frequently Asked Questions
Common questions about solving Battleships in a Board and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Battleships in a Board 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 Battleships in a Board?
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 Battleships in a Board?
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 Battleships in a Board 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 Battleships in a Board 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 Battleships in a Board 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 Battleships in a Board 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 Battleships in a Board 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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