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How to Solve Valid Phone Numbers Problem
Master the Valid Phone Numbers LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsEasy#193
LeetCode ProblemValid Phone Numbers
Given a text file file.txt that contains a list of phone numbers (one per line), write a one-liner bash script to print all valid phone numbers. You may assume that a valid phone number must appear in one of the following two formats: (xxx) xxx-xxxx or xxx-xxx-xxxx. (x means a digit) You may also assume each line in the text file must not contain leading or trailing white spaces. Example: Assume that file.txt has the following content: Your script should output the following valid phone numbers:
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Problem Breakdown
Understanding the Valid Phone Numbers Problem
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Problem Statement
Given a text file file.txt that contains a list of phone numbers (one per line), write a one-liner bash script to print all valid phone numbers. You may assume that a valid phone number must appear in one of the following two formats: (xxx) xxx-xxxx or xxx-xxx-xxxx. (x means a digit) You may also assume each line in the text file must not contain leading or trailing white spaces. Example: Assume that file.txt has the following content: Your script should output the following valid phone numbers:
EasyProblem #193
LeetCodeValid Phone Numbers
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How Phantom Code Helps
Get real-time assistance for Valid Phone Numbers problems during coding interviews. Phantom Code provides instant solutions and explanations.
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Solve Valid Phone Numbers — Given a text file file.txt that contains a list of phone numbers (one per line),...
Here's the optimal approach using Shell:
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 Valid Phone Numbers and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Valid Phone Numbers 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 Valid Phone Numbers?
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 Valid Phone Numbers?
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 Valid Phone Numbers 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 Valid Phone Numbers 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 Valid Phone Numbers 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 Valid Phone Numbers 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 Valid Phone Numbers 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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