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How to Solve Number of Wonderful Substrings Problem
Master the Number of Wonderful Substrings LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsMedium#1915
LeetCode ProblemNumber of Wonderful Substrings
A wonderful string is a string where at most one letter appears an odd number of times. Given a string word that consists of the first ten lowercase English letters ('a' through 'j'), return the number of wonderful non-empty substrings in word. If the same substring appears multiple times in word, then count each occurrence separately. A substring is a contiguous sequence of characters in a string.
Hash TableStringBit ManipulationPrefix Sum
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Problem Breakdown
Understanding the Number of Wonderful Substrings Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
A wonderful string is a string where at most one letter appears an odd number of times. Given a string word that consists of the first ten lowercase English letters ('a' through 'j'), return the number of wonderful non-empty substrings in word. If the same substring appears multiple times in word, then count each occurrence separately. A substring is a contiguous sequence of characters in a string.
MediumProblem #1915
LeetCodeNumber of Wonderful Substrings
Related Topics
Hash TableStringBit ManipulationPrefix Sum
How Phantom Code Helps
Get real-time assistance for Number of Wonderful Substrings problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
word = "aba"
Output
4
# Example 2
Input
word = "aabb"
Output
9
# Example 3
Input
word = "he"
Output
2
Constraints
1 <= word.length <= 105
word consists of lowercase English letters from 'a' to 'j'.
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Solve Number of Wonderful Substrings — A wonderful string is a string where at most one letter appears an odd number of...
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def solve(input):
# Optimal O(n) solution
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Time: O(n) | Space: O(n)
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Frequently Asked Questions
Common questions about solving Number of Wonderful Substrings and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Number of Wonderful Substrings 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 Number of Wonderful Substrings?
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 Number of Wonderful Substrings?
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 Number of Wonderful Substrings 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 Number of Wonderful Substrings 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 Number of Wonderful Substrings 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 Number of Wonderful Substrings 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 Number of Wonderful Substrings 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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