Create MergeSort.java

java/MergeSort.java

@@ -0,0 +1,119 @@
+import java.util.Scanner;
+
+public class MergeSort{
+
+  public static void main(String a[]){
+
+  int temp;
+
+
+Scanner sc=new Scanner (System.in);
+
+System.out.println("Enter N ( how many numbers to be sorted)");
+
+int n = sc.nextInt();
+
+
+int [] list=new int[n];
+
+System.out.println("Enter "+n+ " numbers 1 by 1");
+
+
+for (int i=0 ; i<n; i++)
+
+     {
+
+     int  number = sc.nextInt();
+
+     list[i]=number;
+
+     }
+
+
+  System.out.println("List before  sorting \n");
+
+  for(int i = 0; i < list.length; i++)
+
+      System.out.print( list[i]+"  ");
+
+  System.out.println();
+
+
+  mergeSort(list,0, list.length-1);
+
+
+  System.out.print("List after sorting \n");
+
+  for(int i = 0; i < list.length; i++)
+
+      System.out.print(list[i]+"  ");
+
+  System.out.println();
+
+  }
+
+
+  public static void mergeSort(int list[],int low, int high){
+
+   if (low >= high) 
+          { 
+               return;
+              }   
+
+
+  int middle = (low + high) / 2;          
+
+  mergeSort(list, low, middle);
+
+  mergeSort(list, middle + 1, high);
+
+  merge(list, low,middle,high);
+
+
+       }
+
+
+private static void merge(int list[], int low, int middle, int high)
+
+{
+
+  int IstList_end= middle;
+
+  int IIndList_start = middle + 1;
+
+  int l=low;
+
+  while ((l <= IstList_end) && (IIndList_start <= high))
+
+             {
+
+      if (list[low] < list[IIndList_start]) {
+
+            low++;
+
+         } else {
+
+              int temp = list[IIndList_start];
+
+              for (int j = IIndList_start-1; j >= low; j--) {
+
+              list[j+1] = list[j];
+
+          }
+
+      list[low] = temp;
+
+      low++;
+
+      IstList_end++;
+
+      IIndList_start++;
+
+      }
+
+    }
+
+
+  }  
+
+}