LeetCode 70 - Climbing Stairs Problem

Problem Statement

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

Solution:

#iterative approach class Solution: def climbStairs(self, n: int) -> int: if n==0 or n==1: return n nums = [0 for i in range(n+1)] nums[0]=1 nums[1]=1 for i in range(2, n+1): nums[i] = nums[i-1]+nums[i-2] return nums[n]