MEDIUM Bit Manipulation
461. Hamming Distance
📖 Problem
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.
🧠 Visual Learning Aid
1 Model the input into the right structure
2 Choose the core technique and invariant
3 Execute step-by-step with a sample
4 Validate complexity and edge cases
JS/TS Refreshers
- •Array methods (`push`, `pop`, `shift`, `slice`)
- •Object/Map/Set usage patterns
- •Function parameter and return typing
Logical Thinking Concepts
- •Define invariants before coding
- •Check edge cases first (`[]`, single element, duplicates)
- •Estimate time/space before implementation
💡 Approach
- → XOR x and y: set bits are positions where they differ
- → Count the number of set bits in the XOR result
- → Time: O(1) - max 32 iterations for 32-bit integers, Space: O(1)
- → in popcount, Brian Kernighan's algorithm
🧭 Prerequisites
🛠️ Hints & Pitfalls
Hints
- •XOR x and y: set bits are positions where they differ
- •Count the number of set bits in the XOR result
- •Time: O(1) - max 32 iterations for 32-bit integers, Space: O(1)
Common Pitfalls
- •in popcount, Brian Kernighan's algorithm
🧪 Test Cases
Hidden tests on submit: 1
Test Case 1
Not run Input:
hammingDistance(1, 4); Expected:
2 Test Case 2
Not run Input:
hammingDistance(3, 1); Expected:
1 Test Case 3
Not run Input:
hammingDistance(0, 0); Expected:
0 📝 Code Editor
📤 Output