1791D - Distinct Split - CodeForces Solution

/**
 * author: Ashif Akhtar
 **/
#include <bits/stdc++.h>
using namespace std;

// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;

#define sync ios::sync_with_stdio(0); cin.tie(0); cout.tie(0)
using ll = long long;
using ld = long double;
using uint = unsigned int;
using ull = unsigned long long;
using pii = pair<int, int>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;

#define pb push_back
#define mp make_pair
#define um unordered_map
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
const ll mod = 1000000007;
#define endl "\n"
#define in(x , n) for (auto &i : x)cin >> i;
#define out(x , n) for (int i = 0; i < n; i++)cout << x[i] << " \n"[i == n - 1];
#define pi 3.14159265358979323846

// typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>pb;
#define fo find_by_order
#define ok order_of_key
#define ins insert

void dbg_out() { cerr << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cerr << H << ' '; dbg_out(T...); }

int dx[] = {0, 1, 0, -1, 1, -1, 1, -1};
int dy[] = {1, 0, -1, 0, -1, 1, 1, -1};

void solve()
{
	int n;
	string s;
	cin >> n >> s;
	map<char, int>m1, m2;
	for (int i = 0; i < n; ++i)
	{
		m1[s[i]]++;
	}
	int ans1 = m1.size();
	int ans2 = 0;
	int Ans = ans1;
	for (int i = 0; i < n; ++i)
	{
		m1[s[i]]--;
		if (m1[s[i]] == 0)ans1--;
		m2[s[i]]++;
		ans2 = m2.size();
		Ans = max(ans1 + ans2, Ans);
	}
	cout << Ans << endl;
}

signed main()
{
	sync;
	int t = 1;
	cin >> t;
	for (int i = 1; i <= t; ++i)
	{
		// cout << "Case #" << i << ": ";
		solve();
	}
	return 0;
}