Introduction

In this blog post, we will explore how to solve the LeetCode problem "2275" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

The bitwise AND of an array nums is the bitwise AND of all integers in nums. For example, for nums = [1, 5, 3], the bitwise AND is equal to 1 & 5 & 3 = 1. Also, for nums = [7], the bitwise AND is 7. You are given an array of positive integers candidates. Compute the bitwise AND for all possible combinations of elements in the candidates array. Return the size of the largest combination of candidates with a bitwise AND greater than 0. Example 1: Input: candidates = [16,17,71,62,12,24,14] Output: 4 Explanation: The combination [16,17,62,24] has a bitwise AND of 16 & 17 & 62 & 24 = 16 > 0. The size of the combination is 4. It can be shown that no combination with a size greater than 4 has a bitwise AND greater than 0. Note that more than one combination may have the largest size. For example, the combination [62,12,24,14] has a bitwise AND of 62 & 12 & 24 & 14 = 8 > 0. Example 2: Input: candidates = [8,8] Output: 2 Explanation: The largest combination [8,8] has a bitwise AND of 8 & 8 = 8 > 0. The size of the combination is 2, so we return 2. Constraints: 1 <= candidates.length <= 105 1 <= candidates[i] <= 107

Explanation

• Bit Counting: Iterate through each bit position (from 0 to 24, since the maximum number is 10⁷). For each bit position, count how many numbers in the input array have that bit set.
  • Maximization: The largest combination with a bitwise AND greater than 0 for a given bit is simply the number of elements that have that bit set. Keep track of the maximum count found across all bit positions.
  • Return Max Count: Return the overall maximum count, which represents the size of the largest combination with a bitwise AND > 0.

• Time Complexity: O(n log m), where n is the length of the candidates array and m is the maximum value in the candidates array. Space Complexity: O(1).

Code

    def largestCombination(candidates):
    """
    Finds the size of the largest combination of candidates with a bitwise AND greater than 0.

    Args:
        candidates: A list of positive integers.

    Returns:
        The size of the largest combination with a bitwise AND greater than 0.
    """

    max_count = 0
    for bit in range(25):  # Iterate through bit positions (0 to 24)
        count = 0
        for num in candidates:
            if (num >> bit) & 1:  # Check if the bit is set in the number
                count += 1
        max_count = max(max_count, count)

    return max_count