# LeetCode: Problem 70
# Jonathan Kosasih

#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?
#
#Note: Given n will be a positive integer.
#
#Example 1:
#Input: 2
#Output: 2
#Explanation: There are two ways to climb to the top.
#1. 1 step + 1 step
#2. 2 steps
#
#Example 2:
#Input: 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
#------------------------------------------------------------------
class Solution(object):
    def climbStairs(self, n):
        """
        :type n: int
        :rtype: int
        """
        # only 1 way to make 0 steps (no steps)
        dp = [1] + [0] * n
        # only 1 way to make 1 step
        dp[1] = 1
        for index in range(2,len(dp)):
            dp[index] += dp[index-1] + dp[index-2]
        return dp[-1]
                
sol = Solution()
example = 2
print(sol.climbStairs(example))
example = 3
print(sol.climbStairs(example))
example = 5
print(sol.climbStairs(example))
example = 10
print(sol.climbStairs(example))