Is Hamming Distance easy or hard?

Hamming Distance is classified as an Easy problem. The main insight is recognizing that XOR reveals differing bit positions. Once that idea is clear, counting set bits completes the solution in a few lines of code.

Hamming Distance Python/Java solution

In Python, compute x ^ y and count set bits using bin(x ^ y).count('1') or bit operations. In Java, use Integer.bitCount(x ^ y). Both approaches run in constant time with O(1) space and rely on built-in bit counting utilities.

How to solve Hamming Distance in O(1)?

Compute x ^ y to identify the differing bit positions, then count the number of 1s in the result. Because integer size is fixed, the bit counting step runs in constant time. Many languages also provide built-in functions like popcount to compute the result efficiently.

What is the best approach for Hamming Distance?

The optimal approach uses XOR followed by counting the number of set bits. XOR highlights exactly the positions where two integers differ, turning the problem into a population count task. This solution runs in O(1) time because integers have a fixed bit width and uses O(1) extra space.

Is Hamming Distance asked at Google/Amazon/Meta?

Hamming Distance appears frequently in coding interviews at companies that test bit manipulation fundamentals. Variants or related questions have been reported in interviews at companies such as Amazon, Google, and Meta because they test understanding of XOR and bit counting techniques.

What data structure is used in Hamming Distance?

No specialized data structure is required. The solution relies on bitwise operations such as XOR, AND, and bit shifting. These operations are part of standard integer manipulation and fall under the bit manipulation category.

What is the time complexity of Hamming Distance?

Using the XOR approach, the time complexity is O(1) because at most 32 or 64 bits are processed depending on the integer type. If Brian Kernighan’s algorithm is used, the runtime becomes O(k), where k is the number of differing bits. Space complexity remains O(1).

Description Solution Video 6:25

461. Hamming Distance

Easy76.7% acceptance4 companies

The Hamming distance between two integers is the number of positions at which the corresponding bits are different.

Given two integers x and y, return the Hamming distance between them.

Example 1:

Input: x = 1, y = 4
Output: 2
Explanation:
1   (0 0 0 1)
4   (0 1 0 0)
       ↑   ↑
The above arrows point to positions where the corresponding bits are different.

Example 2: