Climbing Stairs 动态规划

you are climbing a stair case. It takes n steps to reach to the top.
Each time you can either climb 1 or 2 steps. In how many
distinct ways can you climb to the top?

非常简单的动态规划问题

class Solution(object):
    """
    :type n: int
    :rtype: int
    """
    # def getSum(self,n):
    #         if n < 0:
    #             return
    #         elif n == 0:
    #             self.sum+=1
    #             return
    #         self.getSum(n-1)
    #         self.getSum(n-2)
    # def climbStairs(self, n):
    #     self.sum = 0
    #     self.getSum(n)
    #     return self.sum
    # F[k] = F[k-2] + F[k-1]
    def climbStairs(self, n):
        F = []
        for i in range(n+1):
            F.append(0)
        k = 2
        F[1] = F[0] = 1
        while k <= n:
            F[k] = F[k-1] + F[k-2]
            k+=1
        return F[n]