Climbing Stairs

Problem Statement

You are climbing a staircase. It takes n steps to reach the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

LeetCode link

Example 1:

Input: n = 2
Output: 2

Explanation:

There are two ways to climb to the top.

1. 1 step + 1 step
2. 2 steps

Example 2:

Input: n = 3
Output: 3

Explanation:

There are three ways to climb to the top.

1. 1 step + 1 step + 1 step
2. 1 step + 2 steps
3. 2 steps + 1 step

Constraints:

- 1 <= n <= 45

Code

Python Code

class Solution(object):
    def climbStairs(self, n):
    a = b = 1
    for _ in range(n):
        a, b = b, a + b
    return a