# Problem

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?

Example 1:

Input: n = 2 Output: 2 Explanation: There are two ways to climb to the top. 1. 1 step + 1 step 2. 2 steps

Example 2:

Input: n = 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

# Solution

It's Fibonacci!

class Solution(object):
def __init__(self):
self.dic = {1:1, 2:2}
def climbStairs(self, n):
"""
:type n: int
:rtype: int
"""
if n not in self.dic:
self.dic[n] = self.climbStairs(n-1) + self.climbStairs(n-2)
return self.dic[n]