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How to Solve Count Ways To Build Good Strings Problem
Master the Count Ways To Build Good Strings LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsMedium#2466
LeetCode ProblemCount Ways To Build Good Strings
Given the integers zero, one, low, and high, we can construct a string by starting with an empty string, and then at each step perform either of the following: This can be performed any number of times. A good string is a string constructed by the above process having a length between low and high (inclusive). Return the number of different good strings that can be constructed satisfying these properties. Since the answer can be large, return it modulo 109 + 7.
Dynamic Programming
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Problem Breakdown
Understanding the Count Ways To Build Good Strings Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
Given the integers zero, one, low, and high, we can construct a string by starting with an empty string, and then at each step perform either of the following: This can be performed any number of times. A good string is a string constructed by the above process having a length between low and high (inclusive). Return the number of different good strings that can be constructed satisfying these properties. Since the answer can be large, return it modulo 109 + 7.
MediumProblem #2466
LeetCodeCount Ways To Build Good Strings
Related Topics
Dynamic Programming
How Phantom Code Helps
Get real-time assistance for Count Ways To Build Good Strings problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
low = 3, high = 3, zero = 1, one = 1
Output
8
# Example 2
Input
low = 2, high = 3, zero = 1, one = 2
Output
5
Constraints
1 <= low <= high <= 105
1 <= zero, one <= low
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Solve Count Ways To Build Good Strings — Given the integers zero, one, low, and high, we can construct a string by starti...
Here's the optimal approach using Dynamic Programming:
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 Count Ways To Build Good Strings and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Count Ways To Build Good Strings 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 Count Ways To Build Good Strings?
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 Count Ways To Build Good Strings?
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 Count Ways To Build Good Strings 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 Count Ways To Build Good Strings 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 Count Ways To Build Good Strings 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 Count Ways To Build Good Strings 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 Count Ways To Build Good Strings 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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