You are given an integer array cost
where cost[i]
is the cost of ith
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
SOLUTION:
class Solution:
memo = {}
def minCostClimbingStairsRec(self, i, cost):
if i > len(cost) - 1:
return 0
if i == len(cost) - 1:
return cost[i]
if i not in self.memo:
self.memo[i] = cost[i] + min(self.minCostClimbingStairsRec(i + 1, cost), self.minCostClimbingStairsRec(i + 2, cost))
return self.memo[i]
def minCostClimbingStairs(self, cost: List[int]) -> int:
self.memo = {}
return min(self.minCostClimbingStairsRec(0, cost), self.minCostClimbingStairsRec(1, cost))
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