#477 - Total Hamming Distance

Medium • View on LeetCode • View on GitHub

Problem Description

The Hamming distance between two integers is the number of positions at which the corresponding bits are different.

Given an integer array nums, return the sum of Hamming distances between all the pairs of the integers in nums.

Solution

/**
 * @param {number[]} nums
 * @return {number}
 */
var totalHammingDistance = function(nums) {
  let result = 0;

  for (let bit = 0; bit < 32; bit++) {
    const ones = nums.reduce((count, n) => count + ((n >> bit) & 1), 0);
    result += ones * (nums.length - ones);
  }

  return result;
};