0pts求条

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int maxn = 1e5 + 10, maxk = 53;
int n, f[maxn][maxk], b[128], k;
string s;
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	cin >> n >> s;
	for (int i = 0; i < n; i++) if (!b[0 + s[i]]) b[0 + s[i]] = ++k;
	map<vector<int>, int>mp;
	vector<int>tmp(k - 1, 0);
	mp[tmp] = 1;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= k; j++) f[j][i] = f[j][i - 1];
		f[b[0 + s[i - 1]]][i]++;
	}
	int ans = 0;
	for (int i = 1; i <= n; i++) {
		tmp.clear();
		for (int j = 1; j < k; j++) tmp.push_back(f[j][i] - f[j][i - 1]);
		(ans += mp[tmp]) %= (int)(7 + 1e9);
		mp[tmp]++;
	}
	cout << ans;
	return 0;
}