This problem was asked by Amazon.
There exists a staircase with N steps, and you can climb up either 1 or 2 steps at a time.
Given N, write a function that returns the number of unique ways you can climb the staircase. The order of the steps matters.
Input:
n: 4
output: 5
Output explanation:
- 1, 1, 1, 1
- 2, 1, 1
- 1, 2, 1
- 1, 1, 2
- 2, 2