76 lines
2.4 KiB
Java
76 lines
2.4 KiB
Java
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package Sorts;
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import java.util.Arrays;
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import java.util.*;
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/*This code implements the mergeSort algorithm without extra space
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For understanding about mergesort visit :https://www.geeksforgeeks.org/merge-sort/
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*/
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public class MergeSortNoExtraSpace {
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public static void call_merge_sort(int a[],int n)
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{
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int maxele = Arrays.stream(a).max().getAsInt() + 1;
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merge_sort(a,0,n-1,maxele);
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}
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public static void merge_sort(int a[],int start , int end,int maxele){ //this function divides the array into 2 halves
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if(start<end){
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int mid = (start +end)/2;
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merge_sort(a, start,mid,maxele);
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merge_sort(a,mid+1,end,maxele);
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implement_merge_sort(a,start,mid,end,maxele);
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}
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}
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public static void implement_merge_sort(int a[], int start , int mid , int end,int maxele){ //implementation of mergesort
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int i=start;
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int j=mid+1;
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int k =start;
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while (i<=mid && j<=end){
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if(a[i]%maxele<=a[j]%maxele){
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a[k] = a[k] + (a[i]
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% maxele) * maxele;
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k++;
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i++;
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}
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else{
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a[k] = a[k] + (a[j]
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% maxele) * maxele;
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k++;
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j++;
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}
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}
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while(i<=mid){
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a[k] = a[k] + (a[i]
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% maxele) * maxele;
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k++;
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i++;
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}
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while(j<=end){
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a[k] = a[k] + (a[j]
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% maxele) * maxele;
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k++;
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j++;
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}
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for(i=start;i<=end;i++)
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{
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a[i] = a[i] / maxele;
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}
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}
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public static void main(String args[]) {
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Scanner inp=new Scanner(System.in);
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System.out.println("Enter array size");
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int n=inp.nextInt();
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int a[]=new int[n];
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System.out.println("Enter array elements");
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for(int i=0;i<n;i++)
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{
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a[i]=inp.nextInt();
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}
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call_merge_sort(a,n);
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for(int i=0;i<a.length;i++){
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System.out.print(a[i]+" ");
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}
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}
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}
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