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Number of 1 Bits

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Solution write-up

bitsTime: O(k) where k = number of set bitsSpace: O(1)Frequency: 4

Given a positive integer n, write a function that returns the number of set bits in its binary representation (also known as the Hamming weight).

Constraints: 1 <= n <= 2^31 - 1

Example 1:

Input: n = 11
Output: 3
Explanation: The binary string 1011 has a total of three set bits.

Example 2:

Input: n = 128
Output: 1
Explanation: The binary string 10000000 has a total of one set bit.

Example 3:

Input: n = 2147483645
Output: 30
Explanation: The binary string 1111111111111111111111111111101 has a total of thirty set bits.

bit-manipulation

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bitsTime: O(k) where k = number of set bitsSpace: O(1)Frequency: 4

Given a positive integer n, write a function that returns the number of set bits in its binary representation (also known as the Hamming weight).

Constraints: 1 <= n <= 2^31 - 1

Example 1:

Input: n = 11
Output: 3
Explanation: The binary string 1011 has a total of three set bits.

Example 2:

Input: n = 128
Output: 1
Explanation: The binary string 10000000 has a total of one set bit.

Example 3:

Input: n = 2147483645
Output: 30
Explanation: The binary string 1111111111111111111111111111101 has a total of thirty set bits.

bit-manipulation