70. Climbing Stairs

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Description

Easy
Topics
Companies
Hint
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

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Code

func climbStairs(n int) int {
	if n == 1 {
		return 1
	}
	lists := make([]int, 46)
	lists[0] = 1
	lists[1] = 1

	for i := 2; i <= n; i++ {
		lists[i] = lists[i-1] + lists[i-2]
	}

	return lists[n]
}