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How to Solve Number of Ways to Reach a Position After Exactly k Steps Problem
Master the Number of Ways to Reach a Position After Exactly k Steps LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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LeetCode ProblemNumber of Ways to Reach a Position After Exactly k Steps
You are given two positive integers startPos and endPos. Initially, you are standing at position startPos on an infinite number line. With one step, you can move either one position to the left, or one position to the right. Given a positive integer k, return the number of different ways to reach the position endPos starting from startPos, such that you perform exactly k steps. Since the answer may be very large, return it modulo 109 + 7. Two ways are considered different if the order of the steps made is not exactly the same. Note that the number line includes negative integers.
MathDynamic ProgrammingCombinatorics
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Problem Breakdown
Understanding the Number of Ways to Reach a Position After Exactly k Steps Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
You are given two positive integers startPos and endPos. Initially, you are standing at position startPos on an infinite number line. With one step, you can move either one position to the left, or one position to the right. Given a positive integer k, return the number of different ways to reach the position endPos starting from startPos, such that you perform exactly k steps. Since the answer may be very large, return it modulo 109 + 7. Two ways are considered different if the order of the steps made is not exactly the same. Note that the number line includes negative integers.
MediumProblem #2400
LeetCodeNumber of Ways to Reach a Position After Exactly k Steps
Related Topics
MathDynamic ProgrammingCombinatorics
How Phantom Code Helps
Get real-time assistance for Number of Ways to Reach a Position After Exactly k Steps problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
startPos = 1, endPos = 2, k = 3
Output
3
# Example 2
Input
startPos = 2, endPos = 5, k = 10
Output
0
Constraints
1 <= startPos, endPos, k <= 1000
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Solve Number of Ways to Reach a Position After Exactly k Steps — You are given two positive integers startPos and endPos. Initially, you are stan...
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Frequently Asked Questions
Common questions about solving Number of Ways to Reach a Position After Exactly k Steps and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Number of Ways to Reach a Position After Exactly k Steps 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 Ways to Reach a Position After Exactly k Steps?
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 Ways to Reach a Position After Exactly k Steps?
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 Ways to Reach a Position After Exactly k Steps 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 Ways to Reach a Position After Exactly k Steps 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 Ways to Reach a Position After Exactly k Steps 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 Ways to Reach a Position After Exactly k Steps 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 Ways to Reach a Position After Exactly k Steps 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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