[leetcode 75-16] Climbing Stairs

https://leetcode.com/problems/climbing-stairs/

class Solution:
    def climbStairs(self, n: int) -> int:
        if n == 0: return 0
        if n == 1: return 1
        if n == 2: return 2

        dp = [0] * (n+1)
        dp[1] = 1
        dp[2] = 2
        for i in range(3,n+1):
            dp[i] = dp[i-1] + dp[i-2]
        return dp[n]