How do you solve Sum of Two Integers on LeetCode?

Sum of Two Integers (LeetCode #371) can be solved using Brute Force or Optimal Solution. The optimal approach is Optimal Solution with O(1) time complexity and O(1) space complexity. Key insight: Bit manipulation can replace arithmetic operations.

What is the time complexity of Sum of Two Integers?

The optimal solution for Sum of Two Integers runs in O(1) time and uses O(1) space. The time complexity is O(1) because the number of operations is constant, regardless of the size of the integers.

What is the brute force solution for Sum of Two Integers?

The brute force approach for Sum of Two Integers is Brute Force, with O(n²) time complexity and O(1) space complexity. The brute-force approach involves repeatedly adding 1 to the first integer until we reach the second integer. This is a straightforward method but inefficient for larger numbers. The optimal Optimal Solution approach improves this to O(1).

What algorithm or data structure is used to solve Sum of Two Integers?

Sum of Two Integers uses the following concepts: Math, Bit Manipulation. The recommended patterns to study are: Bit Manipulation, Mathematical Operations.

What are the interview tips for Sum of Two Integers?

Explain your thought process clearly; it shows understanding. Practice bit manipulation problems to become comfortable with them. Always consider edge cases, like negative numbers or zero.

What are common mistakes when solving Sum of Two Integers?

Forgetting to handle carry correctly in bit manipulation. Not recognizing that the problem can be solved without traditional operators.

#371

Sum of Two Integers

Medium

MathBit ManipulationBit ManipulationMathematical Operations

LeetCode ↗

Approaches

Brute ForceOptimal

Complexity Comparison

	Brute Force	Optimal Solution★
Time	O(n²)	O(1)
Space	O(1)	O(1)

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Intuition

Time O(1)Space O(1)

Using bit manipulation, we can calculate the sum without using + or - by leveraging the properties of binary addition. This method is efficient and works in constant time.

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Algorithm

2 steps

1Step 1: While b is not zero, do the following: a. Calculate carry as (a & b) << 1. b. Update a to (a ^ b). c. Update b to carry.
2Step 2: When b becomes zero, return a as the sum.

solution.py11 lines

1# Full working Python code
2
3def get_sum(a, b):
4    while b != 0:
5        carry = a & b
6        a = a ^ b
7        b = carry << 1
8    return a
9
10# Example usage
11print(get_sum(1, 2))  # Output: 3

ℹ

Complexity note: The time complexity is O(1) because the number of operations is constant, regardless of the size of the integers.

1Bit manipulation can replace arithmetic operations.
2Understanding binary representation is crucial for efficient solutions.

Solutions and explanations are original Tejav content. Problem titles © LeetCode — use the LeetCode button above for the full problem statement.