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70. Climbing Stairs

Math Dynamic Programming Memoization

Problem - Climbing Stairs

Easy

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

 

Constraints:

  • 1 <= n <= 45

Solutions

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class Solution:
    def climbStairs(self, n: int) -> int:
        i, j = 0, 1
        for _ in range(n):
            i, j = j, i + j

        return j

Submission Stats:

  • Runtime: 0 ms (100.00%)
  • Memory: 17.8 MB (30.32%)