1096B - Substring Removal - CodeForces Solution

#include <bits/stdc++.h>

using namespace std;

#define pb push_back
#define ppb pop_back
#define ff first
#define ss second
#define PI 3.141592653589793238462
#define set_bits __builtin_popcountll
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define cy cout << "YES" << endl
#define cn cout << "NO" << endl
#define cmone cout << -1 << endl
#define itn int
#define int long long

typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;

const int M = 998244353;

// ####################################### DEBUGER ##################################################

#ifndef ONLINE_JUDGE
#define debug(x)       \
    cerr << #x << " "; \
    _print(x);         \
    cerr << endl;
#else
#define debug(x)
#endif

void _print(ll t)
{
    cerr << t;
}
void _print(string t) { cerr << t; }
void _print(char t) { cerr << t; }
void _print(lld t) { cerr << t; }
void _print(double t) { cerr << t; }
void _print(ull t) { cerr << t; }

template <class T, class V>
void _print(pair<T, V> p);
template <class T>
void _print(vector<T> v);
template <class T>
void _print(set<T> v);
template <class T, class V>
void _print(map<T, V> v);
template <class T>
void _print(multiset<T> v);

template <class T, class V>
void _print(pair<T, V> p)
{
    cerr << "{";
    _print(p.ff);
    cerr << ",";
    _print(p.ss);
    cerr << "}";
}
template <class T>
void _print(vector<T> v)
{
    cerr << "[ ";
    for (T i : v)
    {
        _print(i);
        cerr << " ";
    }
    cerr << "]";
}
template <class T>
void _print(set<T> v)
{
    cerr << "[ ";
    for (T i : v)
    {
        _print(i);
        cerr << " ";
    }
    cerr << "]";
}
template <class T>
void _print(multiset<T> v)
{
    cerr << "[ ";
    for (T i : v)
    {
        _print(i);
        cerr << " ";
    }
    cerr << "]";
}
template <class T, class V>
void _print(map<T, V> v)
{
    cerr << "[ ";
    for (auto i : v)
    {
        _print(i);
        cerr << " ";
    }
    cerr << "]";
}

// ########################################################################################################

//----------------------------------------------- SOLVE --------------------------------------------------
/*
        --> READ PROPERLY (READ AGAIN)
        --> THINK > FORMULATE > STRUCTURE CODE > CODE
        --> Check variables, overflows
        --> DEBUG
        --> SUBMIT

        * special cases (n=1?)
        * do something instead of nothing and stay organized
        * WRITE STUFF DOWN
        * DON'T GET STUCK ON ONE APPROACH



*/

void super()
{
    int n;
    cin >> n;
    string s;
    cin >> s;

    if (n == 1)
    {
        cout << 1 << endl;
        return;
    }
    set<char> st;
    for (auto &x : s)
    {
        st.insert(x);
    }

    if (st.size() == 1)
    {
        int ans = (n * (n - 1) / 2)%M;
        cout << ans << endl;
        return;
    }



    int left = 1, right = 1;
    for (int i = 1; i < n; i++)
    {
        if (s[i] == s[i - 1])
            left++;
        else
            break;
    }
    for (int i = n - 2; i >= 0; i--)
    {
        if (s[i] == s[i + 1])
            right++;
        else
            break;
    }

    debug(left);
    debug(right);
    int ans = 0;
    if (s[0] == s[n - 1])
    {
        ans = (left * right) % M;
    }

    ans = (ans + left) % M;
    ans = (ans + right) % M;
    ans = (ans + 1LL) % M;

    cout << ans << endl;
}

// ########################################################################################################

int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int t;
    // cin>>t;
    t = 1;
    while (t--)
    {
        super();
    }

    return 0;
}