1687.-delivering-boxes-from-storage-to-ports.md

1687. Delivering Boxes from Storage to Ports

class Solution:
    def boxDelivering(self, A: List[List[int]], portsCount: int, B: int, W: int) -> int:
        n = len(A)
        need = j = lastj = 0
        dp = [0] + [float('inf')] * n
        for i in range(n):
            while j < n and B > 0 and W >= A[j][1]:
                B -= 1
                W -= A[j][1]
                if j == 0 or A[j][0] != A[j - 1][0]:
                    lastj = j
                    need += 1
                j += 1

            dp[j] = min(dp[j], dp[i] + need + 1)
            dp[lastj] = min(dp[lastj], dp[i] + need)

            B += 1
            W += A[i][1]
            if i == n - 1 or A[i][0] != A[i + 1][0]:
                need -= 1
        return dp[-1]