In this lesson we will introduce you to how challenges work and how to make the most out of them. Let's check your first coding challenge:
Sum of Two Numbers
You are given two numbers a and b and you should return their sum.
Examples:
Input: a = 4, b = 9 Output: 13 Explanation: The sum of a and b is 4 + 9, which is 13.
This is the challenge statement. It explains what the challenge asks us to do and provides some examples to make sure we understand the statement.
Each challenge gives us some input and asks us to write some code that successfully takes that input and uses it to produce some desired output.
In this case, the input is two numbers a and b and the output is their sum.
The class:
If you look at the code editor, you will see that everything is wrapped up inside a class:
class Solution {
}
You don't need to know anything about classes at this point, we will study them in future lessons. Just leave that code untouched.
The method:
Inside this class, we will always be provided with a method. Inside this method is where we should write our solution.
In our case the method is:
public int sum(int a, int b) {
// Your solution goes here!
}
A method is just a function inside a class. When defining methods, we use visibility keywords like public in the method's header. Don't dwell on this, we will study methods in future lessons.
Parameters and return:
This method's parameters will always match the input described in the challenge's statement. In our case, the parameters are a and b, the two numbers we are given.
The method should return a value which represents the desired output described in the challenge's statement. In our case, it should return a + b.
Assignment:
Follow the Coding Tutorial and let's solve our first coding challenge: Sum of Two Numbers
The core challenge of this problem is to correctly implement a function that takes two integers as input and returns their sum. This is a fundamental problem that helps in understanding how to work with basic arithmetic operations and functions in Java.
Significance and common applications include basic arithmetic operations in calculators, financial applications, and any system that requires simple mathematical computations.
Potential pitfalls and misconceptions might include misunderstanding the data types or incorrectly implementing the return statement.
To solve this problem, we need to think about the following steps:
The naive solution is straightforward: simply add the two numbers and return the result. This is optimal for this problem as the operation is O(1) in time complexity.
Here is a step-by-step breakdown of the algorithm:
sum that takes two integer parameters a and b.a and b.public class Solution {
// Method to compute the sum of two numbers
public int sum(int a, int b) {
// Return the sum of a and b
return a + b;
}
}
Explanation of the code:
Solution contains a method sum.sum takes two integer parameters a and b.a and b.The time complexity of this solution is O(1) because the addition operation takes constant time.
The space complexity is also O(1) as we are not using any additional space that grows with the input size.
Potential edge cases include:
sum(0, 0) should return 0.sum(-5, 10) should return 5.sum(-3, -7) should return -10.These edge cases can be tested to ensure the robustness of the solution.
To test the solution comprehensively, consider the following test cases:
sum(4, 9) should return 13.sum(0, 0) should return 0.sum(-5, 10) should return 5.sum(-3, -7) should return -10.Testing frameworks like JUnit can be used to automate these tests.
When approaching such problems, it is important to:
Practicing similar problems and studying algorithms can help improve problem-solving skills.
In this blog post, we discussed how to solve the problem of finding the sum of two numbers in Java. We covered the problem definition, approach, algorithm, code implementation, complexity analysis, edge cases, and testing. Understanding and solving such problems is crucial for developing strong programming skills.
We encourage you to practice and explore further to enhance your understanding and proficiency.
For further reading and practice problems, consider the following resources: