MergeSort code

void MergeSort(int l, int r, int arr[]){
 
    if (l == r)return;
 
    int half = (l + r) / 2;
    int li = l;
    int ri = half + 1;
 
    int idx = l;
 
 
    MergeSort(l, half, arr);
    MergeSort(half + 1, r, arr);
 
    while (li <= half && ri <= r){
 
        if (arr[li] < arr[ri])
            tempBuf[idx++] = arr[li++];
        else
            tempBuf[idx++] = arr[ri++];
 
    }
    while (li <= half) tempBuf[idx++] = arr[li++];
    while (ri <= r) tempBuf[idx++] = arr[ri++];
 
    for (int i = l; i <= r; i++){
        arr[i] = tempBuf[i];
    }
}