Climbing Stairs — LeetCode 70 Python Solution

The problem

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

Example

Input

n = 2

Output

2

Explanation

There are two ways to climb to the top.

Python solution

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

Complexity

Pattern: Dynamic Programming

Define a state, write the transition, and stop recomputing the same subproblem. LeetCode 70. Climbing Stairs is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Dynamic Programming and Memoization.

The dynamic programming guide has the Python template for the pattern and the 481 LeetCode problems that use it.

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