按题意直接模拟即可。

AC code：

#include <bits/stdc++.h>
using namespace std;
int main() {
    int n;
    cin >> n;
    int a[n + 1], sums = 0;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        sums += a[i];
    }
    for (int i = 1; i <= n; i++) {
        if (a[i] * 5 <= sums) {
            for (int j = 1; j <= a[i]; j++) {
                cout << "A";
            }
            cout << endl;
        } else {
            for (int j = 1; j <= a[i]; j++) {
                cout << "B";
            }
            cout << endl;
        }
    }
    return 0;
}

根据题意模拟即可。

#include <bits/stdc++.h>
using namespace std;
int a[112];
int main()
{
	int n;
	cin >> n;
	int s = 0;
	for (int i = 1; i <= n; i++)
	{
		cin >> a[i];
		s += a[i];
	}
	for (int i = 1; i <= n; i++)
	{
		for (int j = 1; j <= a[i]; j++)
			if (a[i] * 5 < s) cout << 'A';
			else cout << 'B';
		cout << endl;
	}
	return 0;
}