2235. Add Two Integers - Detailed Explanation

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Problem Statement

You are given two integers, num1 and num2. The task is to return the sum of these two integers. This is a straightforward problem where you perform basic arithmetic addition.

Example 1

Input: num1 = 12, num2 = 5
Output: 17
Explanation: 12 + 5 equals 17.

Example 2

Input: num1 = -3, num2 = 7
Output: 4
Explanation: -3 + 7 equals 4.

Example 3

Input: num1 = 0, num2 = 0
Output: 0
Explanation: 0 + 0 equals 0.

Approach

This problem is one of the simplest in arithmetic. There is no need for any advanced algorithm or data structure. The solution involves directly adding the two numbers using the addition operator (+).

Steps:

Input Handling:
Receive the two integer inputs, num1 and num2.
Perform Addition:
Use the + operator to compute the sum of num1 and num2.
Return the Result:
Output the computed sum.

Complexity Analysis

Time Complexity:
O(1) – The addition operation takes constant time.
Space Complexity:
O(1) – Only a fixed amount of memory is required regardless of the input values.

Python Code

Python3

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Java Code

Java

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Explanation of the Code

Method addTwoIntegers:
This method takes two integers (num1 and num2) as parameters and returns their sum using the + operator.
Main Method:
- We create an instance of the Solution class.
- We then call the addTwoIntegers method with different test cases.
- The results are printed to the console to verify the correctness of the implementation.

Common Mistakes

Data Type Overflow:
- Pitfall: For very large integers, the sum might exceed the range of a typical integer type.
- Solution: In Java, consider using long if there's a possibility of overflow.
Incorrect Input Parsing:
- Pitfall: In some contexts, inputs might be given as strings; forgetting to convert them to integers can lead to errors.
- Solution: Ensure inputs are parsed to integers before performing the addition.
Misinterpreting the Problem:
- Pitfall: Overcomplicating the problem by adding unnecessary logic or error-checking for an already straightforward arithmetic operation.
- Solution: Focus on the simple arithmetic operation as defined by the problem statement.

Edge Cases

Both Numbers Are Zero:
- Example: num1 = 0, num2 = 0 should return 0.
One Positive and One Negative Number:
- Example: num1 = -3, num2 = 7 should correctly handle the sign and return 4.
Large Numbers:
- Example: If the integers are at the upper bounds of the data type, ensure that the addition does not cause an overflow.
- Note: This is more a concern in strongly-typed languages like Java; consider using larger data types if needed.

Alternative Variations

Addition Without Using the + Operator:
- Some problems require you to implement addition using bit manipulation (e.g., using bitwise XOR and carry operations).
- Related Problem: "371. Sum of Two Integers" on LeetCode.
Subtracting Two Integers:
- A variation where you implement subtraction without using the subtraction operator.
Multiply or Divide Two Integers:
- Variations that ask for multiplication or division implemented without using the standard operators.

Add Two Numbers (Linked List):
- A problem where you add two numbers represented as linked lists.
Sum of Two Integers (Without Using +):
- A common bit manipulation problem that is similar in concept but with constraints on which operators to use.
Arithmetic Operations in Different Bases:
- Problems that require performing addition, subtraction, or multiplication in bases other than 10.