Friday, August 28, 2015

Leetcode: Number of 1 Bits

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.
Special thanks to @ts for adding this problem and creating all test cases.
Understand the problem:
The questions is quite easy to address. Each time we get the least significant bit and check if it is 1. Then shift the number to the right by 1 until 32 times. 

Code (Java):
public class Solution {
    // you need to treat n as an unsigned value
    public int hammingWeight(int n) {
        int result = 0;
        for (int i = 0; i < 32; i++) {
            result += n & 1;
            n = n >> 1;
        return result;

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