Algorithms and Data Structures

  • Profound Academy

    • Status
      • 1
        Implementation
      • 2
        Bitwise operations
      • 3
        Prefix Sums
      • 4
        Sliding window / Two pointers
      • 5
        Modular Arithmetic
      • 6
        Number Theory
      • 7
        Binary Search
      • 8
        Basic Sorting
      • 9
        Greedy Algorithms
      • 10
        Basic Dynamic Programming
      • 11
        Recursion
      • 12
        Linked LIst
      • 13
        Queue & Stack
      • 14
        Binary tree + BST
      • 15
        Divide & Conquer + Advanced Sorting
      • 16
        Heap
      • 17
        Hashing
      • 18
        Graph Representation
      • 19
        BFS

  • Staircase

    You’re climbing a staircase with n stairs. On each step, you can either climb 2 stairs or climb only 1. How many different ways are there to climb those stairs?

    Input

    The input contains a single integer n (1 ≤ n ≤ 45).

    Output

    The output should contain the number of different ways you can climb those staircases.

    Examples

    Input
    Output
    2
    2
    3
    3

    Explanation

    1. For 2 stairs → (1) 1 step + 1 step. (2) 2 steps
    1. For 3 stairs → (1) 1 step + 1 step + 1 step. (2) 1 step + 2 steps. (3) 2 steps + 1 step
     

    Constraints

    Time limit: 1 seconds

    Memory limit: 512 MB

    Output limit: 1 MB

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