Write A Static Method Named NumUnique That Accepts

write Astaticmethod Named Numunique That Accept

Exercise 1 [10 points]: Write a static method named numUnique that accepts an array of integers as a parameter and returns the number of unique values in that array. The array may contain positive integers in no particular order, which means that the duplicates will not be grouped together. For example, if a variable called list stores the following values: int[] list = {7, 5, 22, 7, 23, 9, 1, 5, 2, 35, 6, 11, 12, 7, 9}; then the call of numUnique(list) should return 11 because this list has 11 unique values (1, 2, 5, 6, 7, 9, 11, 12, 22, 23, and 35). It is possible that the list might not have any duplicates. For example if the list contain this sequence of values: int[] list = {1, 2, 11, 17, 19, 20, 23, 24, 25, 26, 31, 34, 37, 40, 41}; Then a call to the method would return 15 because this list contains 15 different values. If passed an empty list, your method should return 0. Note: It might be beneficial to sort the array before you count the unique elements. To sort an integer array, you can use Arrays.sort() method.

Paper For Above instruction

The task at hand involves creating a static method named numUnique that computes the number of unique integers in an array. The method should handle arrays with arbitrary ordering and potentially no duplicates, and should correctly identify and count distinct values, including the edge case of an empty array. This functionality is fundamental in data analysis, set operations, and various computational contexts where identifying unique elements is necessary. The approach includes sorting the array to group duplicates adjacently, simplifying the counting process. After sorting, the method iterates through the array, comparing each element with the previous one to determine whether it is a new unique value. The method then returns the total count of unique values. This approach leverages the efficiency of sorting (O(n log n)) and simple linear traversal (O(n)) to produce an accurate count.

The significance of this task extends beyond simple counting, illustrating core programming concepts such as array manipulation, sorting algorithms, and control flow. Implementing numUnique provides a concrete example of how sorting facilitates duplicate detection and how linear iteration can be used effectively after sorting. Furthermore, this task exemplifies handling special cases, such as empty arrays, which should result in a return value of 0. Efficient implementation and proper handling of edge cases are critical for robust software development, especially in applications dealing with large datasets or requiring high-performance computations.

Implementation

The implementation of numUnique involves several steps:

1. Check if the input array is empty. If so, return 0 immediately.

2. Use Arrays.sort() to sort the array in ascending order. This ensures that duplicate values become adjacent.

3. Initialize a counter to 1 if the array is not empty, since the first element is guaranteed to be unique at this point.

4. Iterate through the array starting from the second element, comparing each element with its predecessor.

5. If a difference is detected, increment the counter, as a new unique value is found.

6. After completing the iteration, return the counter as the total number of unique values.

Sample Code



import java.util.Arrays;


public class UniqueCounter {


public static int numUnique(int[] list) {


if (list == null || list.length == 0) {


return 0;


}


Arrays.sort(list);


int count = 1; // At least one unique value in a non-empty array


for (int i = 1; i 

if (list[i] != list[i - 1]) {


count++;


}


}


return count;


}


}

The code above defines the method and provides a robust approach, including a null check for safety. This method is efficient and straightforward, demonstrating effective use of Java’s standard library functions.

Conclusion

Implementing the numUnique method effectively counts unique elements in an integer array. It employs sorting to simplify duplicate detection and linear traversal for counting. Proper handling of edge cases such as null or empty arrays ensures robustness. This technique exemplifies fundamental programming practices and is applicable in various real-world scenarios involving data deduplication and set operations. The approach combines algorithmic efficiency with simplicity, making it an essential pattern in software development.

References

  • Deitel, H. M., & Deitel, P. J. (2014). Java: How to Program. Pearson.
  • Gaddis, T. (2018). Starting Out with Java: from control structures through data structures. Pearson.
  • Oracle. (2023). Arrays in Java. https://docs.oracle.com/javase/tutorial/java/nutsandbolts/arrays.html
  • Knuth, D. E. (1998). The Art of Computer Programming, Volume 3: Sorting and Searching. Addison-Wesley.
  • Levitin, A. (2012). Introduction to the Design & Analysis of Algorithms. Pearson.
  • Dasgupta, S., Papadimitriou, C., & Vazirani, U. (2008). Algorithms. McGraw-Hill.
  • Sedgewick, R., & Wayne, K. (2011). Algorithms. Addison-Wesley.
  • Mitchell, T. (1997). Machine Learning. McGraw-Hill.
  • Pressman, R. S. (2014). Software Engineering: A Practitioner's Approach. McGraw-Hill.
  • Hochbaum, D. S. (1997). Approximation Algorithms for NP-hard Problems. PWS Publishing.

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