Number Of 1 Bits Problem


Description

LeetCode Problem 191.

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

Note:

  • Note that in some languages, such as Java, there is no unsigned integer type. In this case, the input will be given as a signed integer type. It should not affect your implementation, as the integer’s internal binary representation is the same, whether it is signed or unsigned.
  • In Java, the compiler represents the signed integers using 2’s complement notation. Therefore, in Example 3, the input represents the signed integer. -3.

Example 1:

1
2
3
Input: n = 00000000000000000000000000001011
Output: 3
Explanation: The input binary string 00000000000000000000000000001011 has a total of three '1' bits.

Example 2:

1
2
3
Input: n = 00000000000000000000000010000000
Output: 1
Explanation: The input binary string 00000000000000000000000010000000 has a total of one '1' bit.

Example 3:

1
2
3
Input: n = 11111111111111111111111111111101
Output: 31
Explanation: The input binary string 11111111111111111111111111111101 has a total of thirty one '1' bits.

Constraints:

  • The input must be a binary string of length 32.


Sample C++ Code

1
2
3
4
5
6
7
8
9
10
11
class Solution {
public:
    int hammingWeight(uint32_t n) {
    int sum = 0;
    while (n != 0) {
        sum++;
        n &= (n - 1);
    }
    return sum;
    }
};




Related Posts

Score After Flipping Matrix Problem

LeetCode 861. You are given an m x n binary...

Chalkboard Xor Game Problem

LeetCode 810. You are given an array of integers nums...

Bitwise ORs Of Subarrays Problem

LeetCode 898. We have an array arr of non-negative integers....

Binary Gap Problem

LeetCode 868. Given a positive integer n, find and return...

K-Th Symbol In Grammar Problem

LeetCode 779. We build a table of n rows (1-indexed)....