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111 lines
3.4 KiB
Java
111 lines
3.4 KiB
Java
import java.io.*;
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import java.util.*;
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class HeapSrt
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{
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public int[ ] arr;
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public HeapSrt(int MAX)
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{
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arr=new int[MAX];
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}
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public void makeheap(int n)
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{
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int val,j,father;
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for(int i=1; i<n; i++)
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{
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val=arr[i];
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j=i;
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father=(j-1)/2;//finding the parent of node j
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while(j>0&&arr[father]<val) //creating a MAX heap
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{
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arr[j]=arr[father];//preserving parent dominance
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j=father;
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father=(j-1)/2;
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}
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arr[j]=val;
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}
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}
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void heapsort(int n)
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{
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int k,temp,j;
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for(int i=n-1; i>0; i—)
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{
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temp=arr[i];
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arr[i]=arr[0];
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k=0;
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if(i==1)
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j=-1;
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else
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j=1;
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if(i>2&&arr[2]>arr[1])
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j=2;
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while(j>=0&& temp <arr[j])
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{
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arr[k]=arr[j];
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k=j;
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j=2*k+1;
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if(j+1<=i-1&&arr[j]<arr[j+1])
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j++;
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if(j>i-1)
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j=-1;
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}
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arr[k]=temp;
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}
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}
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/*
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----------------------------------------------------------------------------------
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display: function for displaying the elements
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----------------------------------------------------------------------------------
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*/
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public void display(int n)
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{
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for(int i=0; i<n; i++)
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System.out.println(arr[i]);
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}
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}
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class HeapSrtDemo
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{
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public static void main(String[] args)throws IOException
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{
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HeapSrt obj=new HeapSrt(10);
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int n;
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System.out.println("\n\t Program for Heap Sort ");
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System.out.println("\n How many elements are there?");
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n=getInt();
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System.out.println("\n Enter the elements ");
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for(int i=0; i<n; i++)
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obj.arr[i]=getInt();
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System.out.println("\n The Elements are...");
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obj.display(n);
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obj.makeheap(n);
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System.out.println("\n Heapified");
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obj.display(n);
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obj.heapsort(n);
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System.out.println("\nElements sorted by Heap sort... ");
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obj.display(n);
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}//end of main
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////////////////////////////////////////////////////////////////////////////
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//Following functions are used to handle the inputs entered
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//by the user using keyboard
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////////////////////////////////////////////////////////////////////////////
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public static String getString() throws IOException
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{
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InputStreamReader input=new InputStreamReader(System.in);
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BufferedReader b=new BufferedReader(input);
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String str=b.readLine();//reading the string from console
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return str;
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}
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public static char getChar() throws IOException
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{
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String str=getString();
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return str.charAt(0);//reading first char of console string
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}
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public static int getInt() throws IOException
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{
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String str=getString();
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return Integer.parseInt(str);//converting console string //to numeric value
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}
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}//end of class
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