// C program for Merge Sort 
#include <stdio.h>
#include <stdlib.h>
  
// Merges two subarrays of arr[].
// First subarray is arr[l..m]
// Second subarray is arr[m+1..r]
void merge(int arr[], int l, 
           int m, int r)
{
    int i, j, k;
    int n1 = m - l + 1;
    int n2 = r - m;
  
    // Create temp arrays
    int L[n1], R[n2];
  
    // Copy data to temp arrays 
    // L[] and R[] 
    for (i = 0; i < n1; i++)
        L[i] = arr[l + i];
    for (j = 0; j < n2; j++)
        R[j] = arr[m + 1 + j];
  
    // Merge the temp arrays back 
    // into arr[l..r]
    // Initial index of first subarray
    i = 0; 
  
    // Initial index of second subarray
    j = 0; 
  
    // Initial index of merged subarray
    k = l; 
    while (i < n1 && j < n2) 
    {
        if (L[i] <= R[j]) 
        {
            arr[k] = L[i];
            i++;
        }
        else 
        {
            arr[k] = R[j];
            j++;
        }
        k++;
    }
  
    // Copy the remaining elements 
    // of L[], if there are any
    while (i < n1) {
        arr[k] = L[i];
        i++;
        k++;
    }
  
    // Copy the remaining elements of 
    // R[], if there are any 
    while (j < n2) 
    {
        arr[k] = R[j];
        j++;
        k++;
    }
}
  
// l is for left index and r is 
// right index of the sub-array 
// of arr to be sorted 
void mergeSort(int arr[], 
               int l, int r)
{
    if (l < r) 
    {
        // Same as (l+r)/2, but avoids 
        // overflow for large l and h
        int m = l + (r - l) / 2;
  
        // Sort first and second halves
        mergeSort(arr, l, m);
        mergeSort(arr, m + 1, r);
  
        merge(arr, l, m, r);
    }
}
  
// UTILITY FUNCTIONS 
// Function to print an array 
void printArray(int A[], int size)
{
    int i;
    for (i = 0; i < size; i++)
        printf("%d ", A[i]);
    printf("\n");
}
  
// Driver code
int main()
{
    int arr[] = {12, 11, 13, 5, 6, 7};
    int arr_size = sizeof(arr) / sizeof(arr[0]);
  
    printf("Given array is \n");
    printArray(arr, arr_size);
  
    mergeSort(arr, 0, arr_size - 1);
  
    printf("\nSorted array is \n");
    printArray(arr, arr_size);
    return 0;
}