Merge Sort

// MERGE SORT

#include<stdlib.h>
#include<stdio.h>

void merge(int arr[], int l, int m, int r);
void mergeSort(int arr[], int l, int r);
void printArray(int A[], int size);

int main(){

    srand(5);
    int arr[1000000],i;
    int arr_size = sizeof(arr)/sizeof(arr[0]);

    for(i=0;i<1000000;i++){
        arr[i] = rand() % 100000;
    }

    mergeSort(arr, 0, arr_size - 1);
    //printArray(arr, arr_size);//mozete ispisati niz
    return 0;

}

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 printArray(int A[], int size){

    int i;
    for (i=0; i < size; i++)
        printf("%d\n", A[i]);

}