diff --git a/challenges/Heap_sort.java b/challenges/Heap_sort.java new file mode 100644 index 00000000..0d7f2a23 --- /dev/null +++ b/challenges/Heap_sort.java @@ -0,0 +1,59 @@ +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 l = 2 * i + 1; + int r = 2 * i + 2; + + if (l < n && arr[l] > arr[largest]) + largest = l; + + if (r < n && arr[r] > arr[largest]) + largest = r; + + if (largest != i) { + int swap = arr[i]; + arr[i] = arr[largest]; + arr[largest] = swap; + + heapify(arr, n, largest); + } + } + + static void printArray(int arr[]) + { + int n = arr.length; + for (int i = 0; i < n; ++i) + System.out.print(arr[i] + " "); + System.out.println(); + } + + public static void main(String args[]) + { + 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); + } +}