You are given an integer array cost
where cost[i]
is the cost of i^{th}
step on a staircase. Once you pay the cost, you can either climb one or two steps.
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: 15
Explanation: 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: 6
Explanation: 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

