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How to Solve Find the Lexicographically Smallest Valid Sequence Problem
Master the Find the Lexicographically Smallest Valid Sequence LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsMedium#3302
LeetCode ProblemFind the Lexicographically Smallest Valid Sequence
You are given two strings word1 and word2. A string x is called almost equal to y if you can change at most one character in x to make it identical to y. A sequence of indices seq is called valid if: Return an array of size word2.length representing the lexicographically smallest valid sequence of indices. If no such sequence of indices exists, return an empty array. Note that the answer must represent the lexicographically smallest array, not the corresponding string formed by those indices.
Two PointersStringDynamic ProgrammingGreedy
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Problem Breakdown
Understanding the Find the Lexicographically Smallest Valid Sequence Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
You are given two strings word1 and word2. A string x is called almost equal to y if you can change at most one character in x to make it identical to y. A sequence of indices seq is called valid if: Return an array of size word2.length representing the lexicographically smallest valid sequence of indices. If no such sequence of indices exists, return an empty array. Note that the answer must represent the lexicographically smallest array, not the corresponding string formed by those indices.
MediumProblem #3302
LeetCodeFind the Lexicographically Smallest Valid Sequence
Related Topics
Two PointersStringDynamic ProgrammingGreedy
How Phantom Code Helps
Get real-time assistance for Find the Lexicographically Smallest Valid Sequence problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
word1 = "vbcca", word2 = "abc"
Output
[0,1,2]
# Example 2
Input
word1 = "bacdc", word2 = "abc"
Output
[1,2,4]
# Example 3
Input
word1 = "aaaaaa", word2 = "aaabc"
Output
[]
# Example 4
Input
word1 = "abc", word2 = "ab"
Output
[0,1]
Constraints
1 <= word2.length < word1.length <= 3 * 105
word1 and word2 consist only of lowercase English letters.
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Solve Find the Lexicographically Smallest Valid Sequence — You are given two strings word1 and word2. A string x is called almost equal to ...
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 Find the Lexicographically Smallest Valid Sequence and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Find the Lexicographically Smallest Valid Sequence 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 Find the Lexicographically Smallest Valid Sequence?
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 Find the Lexicographically Smallest Valid Sequence?
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 Find the Lexicographically Smallest Valid Sequence 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 Find the Lexicographically Smallest Valid Sequence 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 Find the Lexicographically Smallest Valid Sequence 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 Find the Lexicographically Smallest Valid Sequence 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 Find the Lexicographically Smallest Valid Sequence 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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