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This Coding & Algorithms question evaluates recursion and dynamic programming concepts by asking for the count of distinct ways to climb n steps, framed at an algorithmic/implementation level. It is commonly asked because it probes recognition of overlapping subproblems and the ability to optimize naive recursive approaches through subproblem reuse and improved time/space efficiency.

  • medium
  • Paradromics
  • Coding & Algorithms
  • Software Engineer

Compute ways to climb n steps

Company: Paradromics

Role: Software Engineer

Category: Coding & Algorithms

Difficulty: medium

Interview Round: Technical Screen

Implement a function that returns the number of distinct ways to reach the top of a staircase with `n` steps if you can climb either 1 or 2 steps at a time. - Input: integer `n` (assume `1 <= n <= 45`) - Output: number of distinct ways Discuss how you would improve a naive recursive solution using dynamic programming (top-down memoization or bottom-up iteration).

Quick Answer: This Coding & Algorithms question evaluates recursion and dynamic programming concepts by asking for the count of distinct ways to climb n steps, framed at an algorithmic/implementation level. It is commonly asked because it probes recognition of overlapping subproblems and the ability to optimize naive recursive approaches through subproblem reuse and improved time/space efficiency.

Return the number of ways to climb n steps taking 1 or 2 steps at a time.

Constraints

  • 1 <= n <= 45

Examples

Input: (1,)

Expected Output: 1

Explanation: One step.

Input: (2,)

Expected Output: 2

Explanation: Two ways.

Input: (5,)

Expected Output: 8

Explanation: Fibonacci relation.

Input: (45,)

Expected Output: 1836311903

Explanation: Upper constraint.

Hints

  1. ways[n] = ways[n-1] + ways[n-2].
Last updated: Jun 27, 2026

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