#2429 - Minimize XOR

Medium • View on LeetCode • View on GitHub

Problem Description

Given two positive integers num1 and num2, find the positive integer x such that:

x has the same number of set bits as num2, and
The value x XOR num1 is minimal.

Note that XOR is the bitwise XOR operation.

Return the integer x. The test cases are generated such that x is uniquely determined.

The number of set bits of an integer is the number of 1's in its binary representation.

Solution

/**
 * @param {number} num1
 * @param {number} num2
 * @return {number}
 */
var minimizeXor = function(num1, num2) {
  let count1 = num1.toString(2).split('1').length - 1;
  const count2 = num2.toString(2).split('1').length - 1;

  while (count1 > count2) {
    num1 &= (num1 - 1);
    count1--;
  }

  while (count1 < count2) {
    num1 |= (num1 + 1);
    count1++;
  }

  return num1;
};