Leetcode 70 Climbing Stairs

class Solution:    # @param {integer} n    # @return {integer}    def climbStairs(self, n):        dp = [0, 1, 2]        i = 3        while i <= n:            dp.append(dp[i-1] + dp[i-2])            i += 1        return dp[n]

class Solution:    # @param {integer} n    # @return {integer}    def climbStairs(self, n):        dp = [1]*(n + 1)        for i in range(2, n + 1):            dp[i] = dp[i-1] + dp[i-2]        return dp[n]