题目
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
思路
动态规划,当前次数等于前一台阶次数+前前台阶次数。
代码
python版本:
class Solution:
def climbStairs(self, n: int) -> int:
dp = [1 for _ in range(n+1)]
for i in range(2, n+1):
dp[i] = dp[i-1]+dp[i-2]
return dp[n]