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How to Solve New 21 Game Problem
Master the New 21 Game 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#837
LeetCode ProblemNew 21 Game
Alice plays the following game, loosely based on the card game "21". Alice starts with 0 points and draws numbers while she has less than k points. During each draw, she gains an integer number of points randomly from the range [1, maxPts], where maxPts is an integer. Each draw is independent and the outcomes have equal probabilities. Alice stops drawing numbers when she gets k or more points. Return the probability that Alice has n or fewer points. Answers within 10-5 of the actual answer are considered accepted.
MathDynamic ProgrammingSliding WindowProbability and Statistics
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Problem Breakdown
Understanding the New 21 Game Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
Alice plays the following game, loosely based on the card game "21". Alice starts with 0 points and draws numbers while she has less than k points. During each draw, she gains an integer number of points randomly from the range [1, maxPts], where maxPts is an integer. Each draw is independent and the outcomes have equal probabilities. Alice stops drawing numbers when she gets k or more points. Return the probability that Alice has n or fewer points. Answers within 10-5 of the actual answer are considered accepted.
MediumProblem #837
LeetCodeNew 21 Game
Related Topics
MathDynamic ProgrammingSliding WindowProbability and Statistics
How Phantom Code Helps
Get real-time assistance for New 21 Game problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
n = 10, k = 1, maxPts = 10
Output
1.00000
# Example 2
Input
n = 6, k = 1, maxPts = 10
Output
0.60000
# Example 3
Input
n = 21, k = 17, maxPts = 10
Output
0.73278
Constraints
0 <= k <= n <= 104
1 <= maxPts <= 104
How Phantom Code Helps with LeetCode Problems
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Solve New 21 Game — Alice plays the following game, loosely based on the card game "21". Alice start...
Here's the optimal approach using Math:
def solve(input):
# Optimal O(n) solution
return result
Time: O(n) | Space: O(n)
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Undetectability Checklist
Run compatibility test before interviews
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Platform Compatibility
Zoom
Supported
Google Meet
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HackerRank
Supported
CodeSignal
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CoderPad
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Teams
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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 New 21 Game and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like New 21 Game 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 New 21 Game?
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 New 21 Game?
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 New 21 Game 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 New 21 Game 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 New 21 Game 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 New 21 Game 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 New 21 Game 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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