Increasing Array

#include <iostream>
using namespace std;
int main()
{
    int n;
    cin >> n;
    int a[n];
    for (int i = 0; i < n; i++)
    {
        cin >> a[i];
    }
    long long r = 0;
    for (int i = 0; i < n - 1; i++)
    {
        if (a[i] > a[i + 1])
        {
            r += a[i] - a[i + 1];
            a[i + 1] = a[i];
        }
    }
    cout << r;
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED