Merge Sort

Merge Sort.cpp

@@ -0,0 +1,99 @@
+#include<iostream>
+using namespace std;
+
+void merge(int arr[], int l, int m, int r)
+{
+    int i, j, k;
+    int n1 = m - l + 1;
+    int n2 =  r - m;
+ 
+    int L[n1], R[n2];
+ 
+   
+    for (i = 0; i < n1; i++)
+        L[i] = arr[l + i];
+    for (j = 0; j < n2; j++)
+        R[j] = arr[m + 1+ j];
+ 
+    i = 0;
+    j = 0;
+    k = l;
+    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++;
+    }
+}
+ 
+
+void mergeSort(int arr[], int l, int r)
+{
+    if (l < r)
+    {
+       
+        int m = l+(r-l)/2;
+ 
+        
+        mergeSort(arr, l, m);
+        mergeSort(arr, m+1, r);
+ 
+        merge(arr, l, m, r);
+    }
+}
+ 
+
+void show(int A[], int size)
+{
+    int i;
+    for (i=0; i < size; i++)
+    cout<<A[i]<<"\n";
+}
+ 
+
+int main()
+{
+     int size;
+    cout<<"\nEnter the number of elements : ";
+
+    cin>>size;
+
+    int arr[size];
+    
+    cout<<"\nEnter the unsorted elements : ";
+
+    for (int i = 0; i < size; ++i)
+    {
+        cout<<"\n";
+        cin>>arr[i];
+    }
+
+    mergeSort(arr, 0, size);
+ 
+    cout<<"Sorted array\n";
+    show(arr, size);
+    return 0;
+}