Heap sort
- 1. Heap Sort PRESENTED BY KHAN MOHAMMAD SHAYSHAB AZAD ID : 161002036
- 2. Heap Sort 1. Heap Sort is a popular and efficient sorting algorithm in computer programming. 2. Heap sort works by visualizing the elements of the array as a special kind of complete binary tree called heap.
- 3. create a complete binary tree from an unsorted list (array) 1. Select first element of the list to be the root node. (First level - 1 element) 2. Put the second element as a left child of the root node and the third element as a right child. (Second level - 2 elements) 3. Put next two elements as children of left node of second level. Again, put the next two elements as children of right node of second level (3rd level - 4 elements). 4. Keep repeating till you reach the last element.
- 4. Heap Data Structure Heap is a special tree-based data structure. A binary tree is said to follow a heap data structure if 1. it is a complete binary tree 2. All nodes in the tree follow the property that they are greater than their children i.e. the largest element is at the root and both its children and smaller than the root and so on. Such a heap is called a max-heap. If instead all nodes are smaller than their children, it is called a min-heap
- 5. “heapify” a tree Starting from a complete binary tree, we can modify it to become a Max-Heap by running a function called heapify on all the non-leaf elements of the heap.
- 6. Procedures to follow for Heapsort 1. Since the tree satisfies Max-Heap property, then the largest item is stored at the root node. 2. Remove the root element and put at the end of the array (nth position) Put the last item of the tree (heap) at the vacant place. 3. Reduce the size of the heap by 1 and heapify the root element again so that we have highest element at root. 4. The process is repeated until all the items of the list is sorted.