Climbing Stairs¶

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?

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

Solution¶

def climbing(n: int):
    if n == 0 or n == 1:
       return 1
    nums = []
    nums.append(1)
    nums.append(1)
    for i in range(2, n + 1):
        result = nums[i - 1] + nums[i - 2]
        nums.append(result)
    return nums[-1]

climbing(4)