leetcode-javascript/191 Number of 1 Bits.js at master · myhaoboyi/leetcode-javascript

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// Leetcode #191

// Language: Javascript

// Problem: https://leetcode.com/problems/number-of-1-bits/

// Author: Chihung Yu

// Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight).

// For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the function should return 3.

// Credits:

// Special thanks to @ts for adding this problem and creating all test cases.

// Hide Company Tags Microsoft Apple

// Hide Tags Bit Manipulation

// Hide Similar Problems (E) Reverse Bits (E) Power of Two (M) Counting Bits

/**

* @param {number} n - a positive integer

* @return {number}

var hammingWeight = function(n) {

if(n === null){

return n;

}

count = 0;

while(n !== 0){

n = n & (n-1);

// use x & (x-1) to determine if an integer is a power of two

// every time you perform the operation x & (x-1), a single 1 bit is erased

count++;

}

return count;

};

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