#2275 - Largest Combination With Bitwise AND Greater Than Zero

Medium • View on LeetCode • View on GitHub

Array Hash Table Bit Manipulation Counting

Problem Description

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.

Solution

/**
 * @param {number[]} candidates
 * @return {number}
 */
var largestCombination = function(candidates) {
  const bitCounts = new Array(32).fill(0);
  let result = 0;

  for (const num of candidates) {
    for (let i = 0; i < 32; i++) {
      if (num & (1 << i)) {
        bitCounts[i]++;
      }
    }
  }

  for (const count of bitCounts) {
    result = Math.max(result, count);
  }

  return result;
};