Climbing Stairs leetcode problem solution DP

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

  Climbing Stairs leetcode problem solution DP-

Problem statement-
Link -https://leetcode.com/problems/climbing-stairs/

You are climbing a staircase. It takes n steps to reach 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

 

Constraints:

• 1 <= n <= 45
• 

Solution -

This problem can be solved by using dp.

Since we know we can climb 1 step or 2 step at a time so our current solution depends on n-1 or n-2 steps solution,

let's say we are at ith stair. we can react at ith stair from i-1 th stair and i-2th stair.

Here is my code-