Cutting Ribbons Python Solution with Tests

lcpy gen -n 1891   # by problem number
lcpy gen -s cutting_ribbons   # by problem name

Input: ribbons = [9,7,5], k = 3
Output: 5
Explanation:
- Cut the first ribbon to two ribbons, one of length 5 and one of length 4.
- Cut the second ribbon to two ribbons, one of length 5 and one of length 2.
- Keep the third ribbon as it is.
Now you have 3 ribbons of length 5.

Input: ribbons = [7,5,9], k = 4
Output: 4
Explanation:
- Cut the first ribbon to two ribbons, one of length 4 and one of length 3.
- Cut the second ribbon to two ribbons, one of length 4 and one of length 1.
- Cut the third ribbon to three ribbons, two of length 4 and one of length 1.
Now you have 4 ribbons of length 4.

Input: ribbons = [5,7,9], k = 22
Output: 0
Explanation: You cannot obtain k ribbons of the same positive integer length.

class Solution:
    # Time: O(n log M) where n = len(ribbons), M = max(ribbons)
    # Space: O(1)
    def max_length(self, ribbons: list[int], k: int) -> int:
        left, right = 1, max(ribbons)
        while left <= right:
            mid = (left + right) // 2
            if sum(r // mid for r in ribbons) >= k:
                left = mid + 1
            else:
                right = mid - 1
        return right