MEDIUM NC#149 Blind #11 Bit Manipulation
371. Sum of Two Integers
📖 Problem
Given two integers a and b, return the sum of the two integers without using the operators + and -.
🧠 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
- •Apply Recursion reasoning pattern
💡 Approach
- → Use XOR for addition without carry: a ^ b
- → Use AND and left shift for carry: (a & b) << 1
- → Repeat until there's no carry
- → Time: O(1) - max 32 iterations for 32-bit integers, Space: O(1)
🧭 Prerequisites
🛠️ Hints & Pitfalls
Hints
- •Use XOR for addition without carry: a ^ b
- •Use AND and left shift for carry: (a & b) << 1
- •Repeat until there's no carry
Common Pitfalls
- •Time: O(1) - max 32 iterations for 32-bit integers, Space: O(1)
🧪 Test Cases
Hidden tests on submit: 1
Test Case 1
Not run Input:
getSum(1, 2); Expected:
3 Test Case 2
Not run Input:
getSum(2, 3); Expected:
5 Test Case 3
Not run Input:
getSum(-1, 1); Expected:
0 📝 Code Editor
📤 Output