## Question

You are given an integer array `cost`

where `cost[i]`

is the cost of `i`

step on a staircase. Once you pay the cost, you can either climb one or two steps.^{th}

You can either start from the step with index `0`

, or the step with index `1`

.

Return *the minimum cost to reach the top of the floor*.

**Example 1:**

Input:cost = [10,15,20]Output:15Explanation:You will start at index 1. - Pay 15 and climb two steps to reach the top. The total cost is 15.

**Example 2:**

Input:cost = [1,100,1,1,1,100,1,1,100,1]Output:6Explanation:You will start at index 0. - Pay 1 and climb two steps to reach index 2. - Pay 1 and climb two steps to reach index 4. - Pay 1 and climb two steps to reach index 6. - Pay 1 and climb one step to reach index 7. - Pay 1 and climb two steps to reach index 9. - Pay 1 and climb one step to reach the top. The total cost is 6.

**Constraints:**

`2 <= cost.length <= 1000`

`0 <= cost[i] <= 999`

## Python Solution

class Solution: def minCostClimbingStairs(self, cost: List[int]) -> int: n = len(cost) if n==0 or n==1:return 0 min_cost_0=cost[0] min_cost_1 = cost[1] for i in range(2,n): min_cost_0,min_cost_1 = min_cost_1,min(min_cost_0,min_cost_1)+cost[i] return min(min_cost_0,min_cost_1)