What is the time complexity of LeetCode 1601. Maximum Number of Achievable Transfer Requests?

The Python solution on this page runs in O(2^m \times (m + n)).

What is the space complexity of LeetCode 1601. Maximum Number of Achievable Transfer Requests?

The Python solution on this page uses O(n), where m and n are the lengths of the room change request list and the number of rooms, respectively auxiliary space.

Maximum Number of Achievable Transfer Requests — LeetCode 1601 Python Solution

HardBit ManipulationArrayBacktrackingEnumeration

Problem: #1601
Pattern: Backtracking
Reading time: 3 min
Source: leetcode.com

The problem

We have n buildings numbered from 0 to n - 1. Each building has a number of employees.

Example

Input: n = 5, requests = [[0,1],[1,0],[0,1],[1,2],[2,0],[3,4]]
Output: 5

Python solution

Python

class Solution:
    def maximumRequests(self, n: int, requests: List[List[int]]) -> int:
        def check(mask: int) -> bool:
            cnt = [0] * n
            for i, (f, t) in enumerate(requests):
                if mask >> i & 1:
                    cnt[f] -= 1
                    cnt[t] += 1
            return all(v == 0 for v in cnt)

        ans = 0
        for mask in range(1 << len(requests)):
            cnt = mask.bit_count()
            if ans < cnt and check(mask):
                ans = cnt
        return ans

Complexity

Measure	Complexity
Time	O(2^m \times (m + n))
Space	O(n), where m and n are the lengths of the room change request list and the number of rooms, respectively auxiliary

Pattern: Backtracking

Build candidates one choice at a time and abandon a branch the moment it cannot work. LeetCode 1601. Maximum Number of Achievable Transfer Requests is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Backtracking.

The backtracking guide has the Python template for the pattern and the 105 LeetCode problems that use it.

Frequently asked questions

How hard is LeetCode 1601. Maximum Number of Achievable Transfer Requests?: LeetCode 1601. Maximum Number of Achievable Transfer Requests is rated Hard on LeetCode.
What is the time complexity of LeetCode 1601. Maximum Number of Achievable Transfer Requests?: The Python solution on this page runs in O(2^m \times (m + n)).
What is the space complexity of LeetCode 1601. Maximum Number of Achievable Transfer Requests?: The Python solution on this page uses O(n), where m and n are the lengths of the room change request list and the number of rooms, respectively auxiliary space.
What topics does LeetCode 1601. Maximum Number of Achievable Transfer Requests cover?: LeetCode 1601. Maximum Number of Achievable Transfer Requests is tagged Bit Manipulation, Array, Backtracking and Enumeration on LeetCode.