求解为什么我只吃右边的糖果也AC了……

#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n, x;
    cin >> n >> x;

    int a[n + 1] = { 0 };
    long long cnt = 0;
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
        if (a[i - 1] + a[i] > x) {
            cnt += a[i - 1] + a[i] - x;
            a[i] = x - a[i - 1];
        }
    }

    cout << cnt;

    return 0;
}