Python3解leetcode Min Cost Climbing Stairs

问题描述：

 

On a staircase, the i-th step has some non-negative cost cost[i]assigned (0 indexed).

 

Once you pay the cost, you can either climb one or two steps. You need to find minimum cost to reach the top of the floor, and you can either start from the step with index 0, or the step with index 1.

 

Example 1:

 

Input: cost = [10, 15, 20]
Output: 15
Explanation: Cheapest is start on cost[1], pay that cost and go to the top.

 

 

 

Example 2:

 

Input: cost = [1, 100, 1, 1, 1, 100, 1, 1, 100, 1]
Output: 6
Explanation: Cheapest is start on cost[0], and only step on 1s, skipping cost[3].

 

 

 

Note:

 

1. cost will have a length in the range [2, 1000].
2. Every cost[i] will be an integer in the range [0, 999].

 

思路：

考虑动态规划算法，依次遍历每一个元素，都计算包含该元素和不包含该元素的结果。

代码：

 

class Solution:
    def minCostClimbingStairs(self, cost: List[int]) -> int:
        notadd , add = 0 , 0
        for i in cost:
            notadd , add = add , i + min(notadd, add)
        return min(notadd , add)