Restyle HearSort.java

public class Solution {
  // Main() for the execution of the program
  public static void main(String args[]) {
    int a[] = {12, 11, 13, 5, 6, 7};
    int len = a.length;

    PrepInsta ob = new PrepInsta();
    ob.sort(a);

    System.out.println("Sorted array is");
    printArray(a);
  }
  public void sort(int a[]) {
    int len = a.length;

    // Build heap (rearrange array)
    for (int i = len / 2 - 1; i >= 0; i--)
      heapify(a, len, i);

    // One by one extract an element from heap
    for (int i = len - 1; i >= 0; i--) {
      // Move current root to end
      int temp = a[0];
      a[0] = a[i];
      a[i] = temp;

      // call max heapify on the reduced heap
      heapify(a, i, 0);
    }
  }

  // To heapify a subtree rooted with node i which is
  // an index in arr[]. n is size of heap
  void heapify(int a[], int len, int i) {
    int largest = i;   // Initialize largest as root
    int l = 2 * i + 1; // left = 2*i + 1
    int r = 2 * i + 2; // right = 2*i + 2

    // If left child is larger than root
    if (l < len && a[l] > a[largest])
      largest = l;

    // If right child is larger than largest so far
    if (r < len && a[r] > a[largest])
      largest = r;

    // If largest is not root
    if (largest != i) {
      int swap = a[i];
      a[i] = a[largest];
      a[largest] = swap;

      // Recursively heapify the affected sub-tree
      heapify(a, len, largest);
    }
  }

  /* A utility function to print array of size n */
  static void printArray(int a[]) {
    int len = a.length;
    for (int i = 0; i < len; ++i)
      System.out.print(a[i] + " ");
    System.out.println();
  }
}