Heap Sort 


 package com.nrs.ds.basic.queue.heap.sort;  
 public class HeapSortImpl {  
      static int total;  
      static void swap(Comparable[] arr, int a , int b){  
           Comparable temp = arr[a];  
           arr[a] = arr[b];  
           arr[b] = temp;  
      }  
      static void heapify(Comparable[] arr , int i){  
           int left = i * 2; //2k  
           int right = i * 2 + 1; // 2k+1  
           int grt = i;  
           if(left <= total && arr[left].compareTo(arr[grt]) >= 0)  
                grt = left;  
           if(right <= total && arr[right].compareTo(arr[grt]) >= 0)  
                grt = right;  
           if(grt != i){  
                swap(arr, i , grt);  
                heapify(arr, grt);  
           }  
      }  
      static void sort(Comparable[] arr){  
           total = arr.length -1;  
           for(int i=total/2; i >=0; i--){  
                heapify(arr, i);  
           }  
           for(int i=total; i > 0; i--){  
                swap(arr, 0,i);  
                total--;  
                heapify(arr, 0);  
           }  
      }  
      public static void main(String[] args) {  
           Integer[] arr= {10, 1, 15, 13, 50, 30, 90};  
           System.out.println("Heap before sort:");  
           for(int i=0;i<arr.length;i++)  
                System.out.println(arr[i]);  
           sort(arr);  
           System.out.println("Heap After sort:");  
           for(int i=0;i<arr.length;i++)  
                System.out.println(arr[i]);  
      }  
 }

Output:


Efficiency :
O(logn) time hippify..
O(nlogn) - n elements.
best for sort-time nlogn , space O(1)

Comments

Post a Comment

Popular posts from this blog

Tournament Tree or Winner Tree

Image
Tournament Tree or Winner Tree :  Is a form of min(max) heap which is a complete binary tree. every external node represents a player and internal node represents a winner. Winner: select the best player among N palyers , (N -1) players to be eliminated. we need minimum of (N-1) games (comparisons). Second best player: we can pick second best player in (N + log2(n-2)) comparisons.   The above tree contains 4 leaf nodes that represent players and have 3 levels 0, 1 and 2. Initially 2 games are conducted at level 2, one between 5 and 3 and another one between 7 and 8. In the next move, one more game is conducted between 5 and 8 to conclude the final winner. Overall we need 3 comparisons. For second best player we need to trace the candidates participated with final winner, that leads to 7 as second best. Uses: Tree selection sort using tournament tree.  
Read more

Linked List

Image
single linked list: 1. Node class NodeLL.java package com.nrs.ds.basic; public class NodeLL { Object value; NodeLL next; public NodeLL(Object value,NodeLL next){ this.value=value; this.next = next; } } 2. LinkedList implementation LinkedListImpl.java package com.nrs.ds.basic; public class LinkedListImpl<T> { NodeLL head; public LinkedListImpl(){ head = null; } public void add(Object value){ NodeLL newNode= new NodeLL(value,null); if(head == null){ head=newNode; }else{ newNode.next = head; head = newNode; } } public void delete(){ head = head.next; } public void display(){ NodeLL n=head; while(n != null){ System.out.println((T)n.value); n = n.next; } } ...
Read more

Heaps

Image
 A Binary Heap is either Min Heap or Max Heap. Min Binary Heap: the key at root must be minimum among all keys present in Binary Heap. the same property must be recursively true for all nodes in Binary Tree. Min Binary Heap: The key at root must be maximum among all keys present in Binary Heap. the same property must be recursively true for all nodes in Binary Tree. Binamial Heap: Binamial Heap  is a Extention of Binary Heap that provides faster union or merge operations together with other operations provided by Binary Heap. Is a collection of tinomial trees. Binamial Tree Tree: A binomial Tree of order 0 has 1 node. A binomial Tree oder k can be constructed by taking two binomial trees of order k-1, and making one as leftmost child of other.  Binomial Heap: Is a set of Binomial Tree where each Binomial Tree follows Min Heap Property. and there can be at-most one Binomial Tree of any degree. Fibonacci Heap:  In terms of Time Com...
Read more