显示原始代码
#include <bits/stdc++.h>
using namespace std;
#define endl "\n"
typedef long long ll;
const int maxN = 2e5 + 10;
void solve() {
int n;
string s;
cin >> n >> s;
ll ans = 0;
vector<int> num(26, 0);
int sz = s.size();
for (int i = sz - 1; i >= 0; i--) {
int k = accumulate(num.begin(), num.end(), 0) - num[s[i] - 'a'];
num[s[i] - 'a'] += (num[s[i] - 'a'] == 0);
num[s[i] - 'a'] += k;
ans += num[s[i] - 'a'];
}
if (sz > 1 && s[0] != s[1])
ans--;
cout << ans << endl;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
int t;
cin >> t;
while (t--) {
solve();
}
return 0;
}