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Print Positive / Negative: Buggy Code in JavaScript (Time Complexity: O(n))


Inside the code editor we've tried to write a function that takes an array nums as argument and for every number in the array:

  • prints "negative" if that number is less than zero

  • or prints the number itself, if the number is greater than or equal to zero

So when we called the function for [2, -12, 0, 4, -5, 3], we expected it to print:

2
negative
0
4
negative
3

but it seems like we made some mistakes because when we run our code, it produces this output:

positive
-12
0
positive
-5
positive

Assignment:

Your task is to fix our loop such that it will print the desired output.

Understanding the Problem

The core challenge of this problem is to correctly identify whether each number in the array is negative or non-negative and print the appropriate output. This problem is significant as it helps in understanding basic conditional statements and loops in JavaScript, which are fundamental concepts in programming.

Common applications of such problems include data validation, filtering data based on conditions, and basic decision-making processes in code.

Potential pitfalls include misunderstanding the conditions for checking negative numbers and incorrectly implementing the loop or conditional statements.

Approach

To solve this problem, we need to iterate through each element of the array and check if it is less than zero. If it is, we print "negative". Otherwise, we print the number itself.

Let's start with a naive approach and then optimize it:

Naive Approach

The naive approach involves using a simple loop to iterate through the array and an if-else statement to check the condition. This approach is straightforward but can be prone to errors if not implemented correctly.

Optimized Approach

The optimized approach is similar to the naive approach but ensures that the conditions are checked correctly and the loop is implemented properly. We will use a for loop to iterate through the array and an if-else statement to check the conditions.

Algorithm

Here is a step-by-step breakdown of the algorithm:

  1. Initialize a function that takes an array as an argument.
  2. Use a for loop to iterate through each element of the array.
  3. Inside the loop, use an if-else statement to check if the current element is less than zero.
  4. If the element is less than zero, print "negative".
  5. Otherwise, print the element itself.

Code Implementation

function printPositiveNegative(nums) {
  // Iterate through each element in the array
  for (let i = 0; i < nums.length; i++) {
    // Check if the current element is less than zero
    if (nums[i] < 0) {
      console.log("negative"); // Print "negative" if the element is less than zero
    } else {
      console.log(nums[i]); // Print the element itself if it is greater than or equal to zero
    }
  }
}

// Test the function with the given example
printPositiveNegative([2, -12, 0, 4, -5, 3]);

Complexity Analysis

The time complexity of this approach is O(n), where n is the number of elements in the array. This is because we are iterating through each element of the array once.

The space complexity is O(1) as we are not using any additional space that scales with the input size.

Edge Cases

Potential edge cases include:

  • An empty array: The function should handle this gracefully without any errors.
  • An array with all negative numbers: The function should print "negative" for each element.
  • An array with all non-negative numbers: The function should print each number itself.

Examples of edge cases and their expected outputs:

[] // No output
[-1, -2, -3] // negative
negative
negative
[0, 1, 2] // 0
1
2

Testing

To test the solution comprehensively, we should include a variety of test cases, from simple to complex:

  • Test with an empty array.
  • Test with an array of all negative numbers.
  • Test with an array of all non-negative numbers.
  • Test with a mixed array of negative and non-negative numbers.

We can use console.log to verify the outputs manually or use a testing framework like Jest for automated testing.

Thinking and Problem-Solving Tips

When approaching such problems, it is important to:

  • Understand the problem statement clearly.
  • Break down the problem into smaller steps.
  • Think about edge cases and how to handle them.
  • Write clean and readable code with comments.
  • Test the solution with a variety of test cases.

To develop problem-solving skills, practice solving similar problems and study different algorithms and their implementations.

Conclusion

In this blog post, we discussed how to fix a buggy code that prints "negative" for negative numbers and the number itself for non-negative numbers. 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 readers to practice and explore further to improve their problem-solving abilities.

Additional Resources

For further reading and practice problems related to this topic, check out the following resources: