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Exp12.java
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Exp12.java
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import java.util.Scanner;
public class HeapSort {
public void sort(int arr[]) {
int n = arr.length;
// Build heap (rearrange array)
for (int i = n / 2 - 1; i >= 0; i--)
heapify(arr, n, i);
// One by one extract an element from heap
for (int i = n - 1; i >= 0; i--) {
// Move current root to end
int temp = arr[0];
arr[0] = arr[i];
arr[i] = temp;
// call max heapify on the reduced heap
heapify(arr, i, 0);
}
}
// To heapify a subtree rooted with node i which is
// an index in arr[]. n is size of heap
void heapify(int arr[], int n, 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 < n && arr[l] > arr[largest])
largest = l;
// If right child is larger than largest so far
if (r < n && arr[r] > arr[largest])
largest = r;
// If largest is not root
if (largest != i) {
int swap = arr[i];
arr[i] = arr[largest];
arr[largest] = swap;
// Recursively heapify the affected sub-tree
heapify(arr, n, largest);
}
}
/* A utility function to print array of size n */
static void printArray(int arr[]) {
int n = arr.length;
for (int i = 0; i < n; ++i)
System.out.print(arr[i] + " ");
System.out.println();
}
// Driver program
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
int n; // Declare array size
System.out.println("Enter the total number of elements ");
n = sc.nextInt(); // Initialize array size
int arr[] = new int[n]; // Declare the array
System.out.println("Enter the elements of the array ");
for (int i = 0; i < n; i++) // Initialize the array
{
arr[i] = sc.nextInt();
}
//int arr[] = { 12, 11, 13, 5, 6, 7 };
//int n = arr.length;
HeapSort ob = new HeapSort();
ob.sort(arr);
System.out.println("Sorted array is");
printArray(arr);
}
}