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How to Solve Separate Black and White Balls Problem
Master the Separate Black and White Balls 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.
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Start Free for WindowsMedium#2938
LeetCode ProblemSeparate Black and White Balls
There are n balls on a table, each ball has a color black or white. You are given a 0-indexed binary string s of length n, where 1 and 0 represent black and white balls, respectively. In each step, you can choose two adjacent balls and swap them. Return the minimum number of steps to group all the black balls to the right and all the white balls to the left.
Two PointersStringGreedy
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Problem Breakdown
Understanding the Separate Black and White Balls Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
There are n balls on a table, each ball has a color black or white. You are given a 0-indexed binary string s of length n, where 1 and 0 represent black and white balls, respectively. In each step, you can choose two adjacent balls and swap them. Return the minimum number of steps to group all the black balls to the right and all the white balls to the left.
MediumProblem #2938
LeetCodeSeparate Black and White Balls
Related Topics
Two PointersStringGreedy
How Phantom Code Helps
Get real-time assistance for Separate Black and White Balls problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
s = "101"
Output
1
# Example 2
Input
s = "100"
Output
2
# Example 3
Input
s = "0111"
Output
0
Constraints
1 <= n == s.length <= 105
s[i] is either '0' or '1'.
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Solve Separate Black and White Balls — There are n balls on a table, each ball has a color black or white. You are give...
Here's the optimal approach using Two Pointers:
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 Separate Black and White Balls and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Separate Black and White Balls 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 Separate Black and White Balls?
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 Separate Black and White Balls?
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 Separate Black and White Balls 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 Separate Black and White Balls 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 Separate Black and White Balls 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 Separate Black and White Balls 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 Separate Black and White Balls 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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