11364 - Parking.cpp

#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);
    }
}

int main()
{
    int cas, shopsNumber;

    cin>>cas;

    for(int i=1; i<=cas; i++)
    {
        cin>>shopsNumber;
        int stores[shopsNumber];

        for(int i=0; i<shopsNumber; i++)
            cin>>stores[i];

        mergeSort(stores, 0, shopsNumber - 1);

        int sum = 0;

        for(int i=shopsNumber-1; i>0; i--)
            sum = sum + (stores[i] - stores[i-1]);

        cout<<sum*2<<endl;

    }

    return 0;
}