[LeetCode][70]climbing-stairs

Content

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
Related Topics
  • 记忆化搜索
  • 数学
  • 动态规划

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  • Solution

    1. 动态规划

    Java

    class Solution {
        public int climbStairs(int n) {
            // 1 <= n <= 45
            // dp[i]表示爬到i位置可能存在的不重复的方案数
            int[] dp = new int[n + 1];
            dp[0] = 1;
            dp[1] = 1;
            for (int i = 2; i <= n; i++) {
                dp[i] = dp[i - 1] + dp[i - 2];
            }
            return dp[n];
        }
    }
    
    posted @ 2023-08-18 15:28  shea24  阅读(10)  评论(0)    收藏  举报