70. 爬楼梯 @Python @Go

原题

https://leetcode.cn/problems/climbing-stairs/description/

思路

动态规划 + 字典

复杂度

时间：O(n)
空间：O(n)

Python代码

class Solution:
    def climbStairs(self, n: int) -> int:
        d = {1: 1, 2: 2}
        if n <= 2:
            return d[n]
        for i in range(3, n+1):
            d[i] = d[i-1] + d[i-2]
        return d[n]        

Go代码

func climbStairs(n int) int {
	d := map[int]int{1: 1, 2: 2}
	if n <= 2 {
		return d[n]
	}
	for i := 3; i <= n; i++ {
		d[i] = d[i-1] + d[i-2]
	}
	return d[n]
}