Last week, the Syrian Olympiad of Informatics finale took place, featuring a problem closely resembling the one found here Maximum Subarray Sum. The twist in this problem included an additional array, named B, where all elements $$$B_i \geq K$$$. The task was to find the Maximum Subarray Sum such that the sum of array $$$B$$$ for that subarray was less or equal than a given integer $$$K$$$.

For instance, with $$$N = 8$$$ and $$$K = 17$$$, given arrays: - Array A: -1 3 -2 5 3 -5 2 2 - Array B: 0 1 15 3 5 0 8 8

The correct answer wouldn't be 9, but 8 since there's a 15 blocking you from adding it. In the test, Also you can simply print 0 if the maximum answer is negative.

I approached this problem using the two-pointers technique, while I also explored a solution on USACO that utilized a set. My solution received an Accepted verdict on the CSES platform, but unfortunately, it failed a testcase on the SOI.

void solve() {
    int n;
    cin >> n;
    int a[n + 1];
    a[0] = 0;
    for (int i = 1; ++i)
        cin >> a[i], a[i] += a[i - 1];
    int l = 0, r = 1, mx = -1e18;
    while (l <= n && r <= n) {
        while (a[r] - a[l] < 0) {
            ++l;
            mx = max(mx, a[r] - a[l]);
            if (l > r)
                r = l;
            mx = max(mx, a[r] - a[l]);
        }

        if (l > r)
            r = l;
        mx = max(a[r] - a[l], mx);
        ++r;
    }

    if (mx == 0) {
        mx = -1e18;
        for (int i = 0; i < n; ++i) {
            mx = max(mx, a[i + 1] - a[i]);
        }
    }

    cout << mx;
}

I may have wrote a different code cause I was sick, Idk, can someone telll me a case I fail?