Problems with Heap Sort Implementation in Java - Incorrect Output for Large Inputs
I keep running into I've encountered a strange issue with I'm working with an scenario with my Heap Sort implementation in Java... The algorithm seems to work fine for smaller arrays, but as the input size increases, it produces incorrect results. For instance, when I try to sort an array of 10,000 random integers, the output is not sorted correctly, and I'm not seeing any obvious exceptions or errors. Here’s the code I’m using: ```java public class HeapSort { public void sort(int arr[]) { int n = arr.length; for (int i = n / 2 - 1; i >= 0; i--) { heapify(arr, n, i); } for (int i = n - 1; i >= 0; i--) { int temp = arr[0]; arr[0] = arr[i]; arr[i] = temp; heapify(arr, i, 0); } } void heapify(int arr[], int n, int i) { int largest = i; int left = 2 * i + 1; int right = 2 * i + 2; if (left < n && arr[left] > arr[largest]) { largest = left; } if (right < n && arr[right] > arr[largest]) { largest = right; } if (largest != i) { int swap = arr[i]; arr[i] = arr[largest]; arr[largest] = swap; heapify(arr, n, largest); } } } ``` To test it, I used the following: ```java public class Main { public static void main(String[] args) { HeapSort hs = new HeapSort(); int[] randomNumbers = new int[10000]; for (int i = 0; i < randomNumbers.length; i++) { randomNumbers[i] = (int)(Math.random() * 10000); } hs.sort(randomNumbers); // Check if sorted for (int i = 0; i < randomNumbers.length - 1; i++) { if (randomNumbers[i] > randomNumbers[i + 1]) { System.out.println("Array not sorted correctly!"); } } } } ``` When the program runs, I sometimes see the message indicating that the array is not sorted correctly, especially for larger inputs. I suspect it might be a question with the heapify process, particularly with how I'm managing indices. I’ve debugged by printing the array at various stages, but I can’t seem to pinpoint where things go wrong. Any insights on what might be causing this scenario, or how to resolve it? I'm using Java 11. I'm coming from a different tech stack and learning Java. Hoping someone can shed some light on this.