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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?

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:
    def climbStairs(self, n: int) -> int:
        one, two = 1, 1

        for i in range(n-1):
            temp = one
            one = one + two
            two = temp
        return one