Furthest Building You Can Reach

class Solution:
    def furthestBuilding(self, heights: List[int], bricks: int, ladders: int) -> int:
        pq = []
        n = len(heights)
        remSum = 0

        ans = n-1
        for i in range(1, n):
            x = max(heights[i] - heights[i-1], 0)

            if x == 0:
                continue

            heappush(pq, x)
            if len(pq) > ladders:
                remSum += heappop(pq)

            if remSum > bricks:
                ans = i-1
                break

        return ans