MergeSort

scripts/MergeSort.java

@@ -0,0 +1,98 @@
+import java.util.*;
+
+class Merge_Sort
+{
+	static void printArray(int arr[])
+    {
+        int n = arr.length;
+        for (int i=0; i<n; ++i)
+            System.out.print(arr[i] + " ");
+        System.out.println();
+    }
+
+    static void mergeSort(int arr[], int l, int r)
+    {
+        GfG g = new GfG();
+        if (l < r)
+        {
+            int m = (l+r)/2;
+            mergeSort(arr, l, m);
+            mergeSort(arr , m+1, r);
+            g.merge(arr, l, m, r);
+        }
+    }
+
+	public static void main(String args[])
+	{
+		Scanner sc = new Scanner(System.in);
+		int T = sc.nextInt();
+		while(T>0)
+		{
+			int n = sc.nextInt();
+			Merge_Sort ms = new Merge_Sort();
+			int arr[] = new int[n];
+			for(int i=0;i<n;i++)
+				arr[i] = sc.nextInt();
+
+			GfG g = new GfG();
+			mergeSort(arr,0,arr.length-1);
+
+			ms.printArray(arr);
+		T--;
+		}
+	}
+}
+
+
+// } Driver Code Ends
+/* The task is to complete merge() which is used
+in below mergeSort() */
+class GfG
+{
+   // Merges two subarrays of arr[].  First subarray is arr[l..m]
+   // Second subarray is arr[m+1..r]
+    void merge(int arr[], int low, int mid, int high)
+    {
+        int n1=mid-low+1;
+        int n2=high-mid;
+        int L[]=new int[n1];
+        int R[]=new int[n2];
+
+        for(int i=0;i<n1;i++)
+        L[i]=arr[low+i];
+
+        for(int j=0;j<n2;j++)
+        R[j]=arr[mid+1+j];
+
+        int k=low,i=0,j=0;
+        while(i<n1 && j<n2)
+        {
+            if(L[i]<=R[j])
+            {
+                arr[k]=L[i];
+                i++;
+            }
+            else
+            {
+                arr[k]=R[j];
+                j++;
+            }
+            k++;
+        }
+
+        while(i<n1)
+        {
+            arr[k]=L[i];
+            i++;
+            k++;
+        }
+        while(j<n2)
+        {
+            arr[k]=R[j];
+            j++;
+            k++;
+        }
+
+
+    }
+}