Capacity To Ship Packages Within D Days — LeetCode 1011 Python Solution

The problem

A conveyor belt has packages that must be shipped from one port to another within days days. The ith package on the conveyor belt has a weight of weights[i].

Example

Input

weights = [1,2,3,4,5,6,7,8,9,10], days = 5

Output

15

Explanation

A ship capacity of 15 is the minimum to ship all the packages in 5 days like this:

Python solution

class Solution:
    def shipWithinDays(self, weights: List[int], days: int) -> int:
        def check(mx):
            ws, cnt = 0, 1
            for w in weights:
                ws += w
                if ws > mx:
                    cnt += 1
                    ws = w
            return cnt <= days

        left, right = max(weights), sum(weights) + 1
        return left + bisect_left(range(left, right), True, key=check)

Complexity

Pattern: Monotonic Stack

Answer "what is the next greater element" for every position in one pass. LeetCode 1011. Capacity To Ship Packages Within D Days is filed here because the reference solution below belongs to the algorithm family this hub collects, even though its LeetCode tags point elsewhere.

The monotonic stack guide has the Python template for the pattern and the 225 LeetCode problems that use it.

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