1687. Delivering Boxes from Storage to Ports

class Solution:
    def boxDelivering(
        self, boxes: List[List[int]], portsCount: int, maxBoxes: int, maxWeight: int
    ) -> int:
        n = len(boxes)
        ws = list(accumulate((box[1] for box in boxes), initial=0))
        c = [int(a != b) for a, b in pairwise(box[0] for box in boxes)]
        cs = list(accumulate(c, initial=0))
        f = [0] * (n + 1)
        q = deque([0])
        for i in range(1, n + 1):
            while q and (i - q[0] > maxBoxes or ws[i] - ws[q[0]] > maxWeight):
                q.popleft()
            if q:
                f[i] = cs[i - 1] + f[q[0]] - cs[q[0]] + 2
            if i < n:
                while q and f[q[-1]] - cs[q[-1]] >= f[i] - cs[i]:
                    q.pop()
                q.append(i)
        return f[n]