Increasing Array

#include <iostream>
#include <vector>

using namespace std;

int main() {
    int n;
    cin >> n;
    vector<long long int> v;
    long long int ans = 0;
    long long int x = 0;
    cin >> x;
    v.push_back(x);
    for (int i = 1; i < n; i++) {
        cin >> x;
        v.push_back(x);
        ans += (v[i - 1] > v[i] ? v[i - 1] - v[i] : 0);
        v[x] += ans;
    }
    cout << ans;
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: RUNTIME ERROR

Test 7

Verdict: ACCEPTED