climbingstairs.py

'''
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?

'''

class Solution:
    def climbStairs(self, n: int) -> int:
        first = 1
        second = 1
        
        for i in range(n - 1):
            first, second = first + second, first
        return first