[LeetCode] 746. Min Cost Climbing Stairs

轉自LeetCode

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

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

Note: Given n will be a positive integer.

Example 1:

Input: 2
Output: 2
Explanation: There are two ways to climb to the top.
1. 1 step + 1 step
2. 2 steps

Example 2:

Input: 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

<Solution>

想法如下

• 用 recursive 會 TLE，必須優化，所以考慮 DP 來優化

• 用 dp[i] 來表示在 i 所要花費的最少 cost，公式是 dp[i] = cost[i] + min(dp[i-1], dp[i-2])

code 如下

Java

kotlin