Is Number Negative? (Time Complexity: O(1), Language: Java)
## Understanding the Problem
The problem is straightforward: we need to determine if a given number `n` is negative or not. If `n` is less than zero, we print "negative"; otherwise, we print "positive".
### Input and Output Formats
- **Input**: A single integer `n`.
- **Output**: A string, either "negative" or "positive".
### Constraints and Assumptions
- The input will always be an integer.
- There are no constraints on the range of the integer.
### Example to Illustrate the Problem
**Example 1:**
Input: n = 5
Output: "positive"
Explanation: 5 is greater than or equal to zero, so our function prints "positive" to the console.
**Example 2:**
Input: n = 0
Output: "positive"
Explanation: 0 is greater than or equal to zero, so our function prints "positive" to the console.
**Example 3:**
Input: n = -2
Output: "negative"
Explanation: -2 is less than zero, so our function prints "negative" to the console.
## Core Challenge
The core challenge is to correctly identify whether the number is negative or not. This is a fundamental problem that can be solved using basic conditional statements.
### Significance and Applications
This problem is a basic example of using conditional statements, which are fundamental in programming. Understanding how to use these statements is crucial for more complex decision-making processes in software development.
### Potential Pitfalls and Misconceptions
- Misunderstanding the condition: Ensure that the condition `n < 0` is correctly implemented.
- Handling edge cases like zero: Remember that zero is not negative.
## Approach
### Naive Solution
The naive solution involves using an `if-else` statement to check if the number is less than zero.
#### Why It Is Not Optimal
In this case, the naive solution is actually optimal because the problem is simple and the `if-else` statement is the most straightforward and efficient way to solve it.
### Optimized Solution
Since the naive solution is already optimal, there is no need for further optimization.
## Algorithm
1. Take the input number `n`.
2. Use an `if` statement to check if `n` is less than zero.
3. If true, print "negative".
4. Otherwise, print "positive".
## Code Implementation
Here is the Java code to solve the problem:
public class Main {
public static void main(String[] args) {
// Test cases
checkNumber(5); // Output: positive
checkNumber(0); // Output: positive
checkNumber(-2); // Output: negative
}
/**
* This function checks if the number is negative or positive.
* @param n the number to check
*/
public static void checkNumber(int n) {
if (n < 0) {
System.out.println("negative");
} else {
System.out.println("positive");
}
}
}
### Explanation of the Code
- The `checkNumber` function takes an integer `n` as input.
- It uses an `if-else` statement to check if `n` is less than zero.
- Depending on the result, it prints either "negative" or "positive".
## Complexity Analysis
### Time Complexity
The time complexity of this solution is O(1) because the check and print operations take constant time.
### Space Complexity
The space complexity is O(1) as well, since no additional space is required beyond the input number.
## Edge Cases
- **Zero**: The function correctly identifies zero as "positive".
- **Negative Numbers**: Any negative number will be correctly identified as "negative".
- **Positive Numbers**: Any positive number will be correctly identified as "positive".
### Examples of Edge Cases
- `n = 0` should output "positive".
- `n = -1` should output "negative".
- `n = 1` should output "positive".
## Testing
To test the solution comprehensively:
1. Use a variety of test cases, including positive numbers, negative numbers, and zero.
2. Ensure the function handles edge cases correctly.
### Test Cases
- `checkNumber(5)` should print "positive".
- `checkNumber(0)` should print "positive".
- `checkNumber(-2)` should print "negative".
## Thinking and Problem-Solving Tips
- Always start by understanding the problem and identifying the core challenge.
- Use simple and efficient solutions for straightforward problems.
- Practice using conditional statements as they are fundamental in programming.
## Conclusion
This problem is a basic example of using conditional statements to make decisions in code. Understanding and solving such problems is crucial for developing more complex algorithms and software.
## Additional Resources
- [Java Documentation](https://docs.oracle.com/javase/8/docs/api/)
- [Conditional Statements in Java](https://www.geeksforgeeks.org/decision-making-javaif-else-switch-break-continue-jump/)
- [Practice Problems on LeetCode](https://leetcode.com/)
By practicing and understanding these fundamental concepts, you can build a strong foundation in programming and problem-solving.
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