基本照抄答案了，还是不对，哪里出问题了

#include<bits/stdc++.h>
using namespace std;
int arr[] = { 0 };
long long M(int l, int r)
{
	if (abs(l - r) > 5) {
		int mid = (l + r) / 2;
		return M(l, mid) % max(M(mid + 1, r), 7ll) + arr[mid] - 1;
	}
	else {
		int max1 = 0;
		for (int i = l; i <= r; i++) {
			max1 = max(max1, arr[i]);
		}
		return max1;
	}
}
int main() {
	int n;
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> arr[i];
	}
	cout << M(1, n);
	return 0;
}