HardNo. 2172

Maximum AND Sum of Array — LeetCode 2172 Python Solution

Topics
Bit Manipulation, Array, Dynamic Programming, Bitmask
Reading time
3 min

The problem

You are given an integer array nums of length n and an integer numSlots such that 2 * numSlots >= n. There are numSlots slots numbered from 1 to numSlots.

Example

Input
nums = [1,2,3,4,5,6], numSlots = 3
Output
9
Explanation
One possible placement is [1, 4] into slot 1, [2, 6] into slot 2, and [3, 5] into slot 3.

Python solution

PythonSolution
class Solution:
    def maximumANDSum(self, nums: List[int], numSlots: int) -> int:
        n = len(nums)
        m = numSlots << 1
        f = [0] * (1 << m)
        for i in range(1 << m):
            cnt = i.bit_count()
            if cnt > n:
                continue
            for j in range(m):
                if i >> j & 1:
                    f[i] = max(f[i], f[i ^ (1 << j)] + (nums[cnt - 1] & (j // 2 + 1)))
        return max(f)

Complexity

Time
O(n·m) (typical)
Space · auxiliary
O(n·m)or optimized

Pattern: Bit Manipulation

Use XOR, masks and the low-bit trick to replace whole data structures with an integer. LeetCode 2172. Maximum AND Sum of Array is filed here because LeetCode tags it Bit Manipulation and Bitmask, which is the vocabulary this hub collects.

The bit manipulation guide has the Python template for the pattern and the 194 LeetCode problems that use it.

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Frequently asked questions

How hard is LeetCode 2172. Maximum AND Sum of Array?

LeetCode 2172. Maximum AND Sum of Array is rated Hard on LeetCode.

What topics does LeetCode 2172. Maximum AND Sum of Array cover?

LeetCode 2172. Maximum AND Sum of Array is tagged Bit Manipulation, Array, Dynamic Programming and Bitmask on LeetCode.

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