Playlist.cpp

///==================================================///
///                HELLO WORLD !!                    ///
///                  IT'S ME                         ///
///               YASH BARJATYA                    ///
///         [ yashbarjatya11@gmail.com ]              ///
///==================================================///
#include <bits/stdc++.h>
using namespace std;
#define fastio()                      \
    ios_base::sync_with_stdio(false); \
    cin.tie(NULL);                    \
    cout.tie(NULL)
#define MOD 1000000007
#define MOD1 998244353
#define INF 1e9 + 10
#define INF_LL 1e18 + 10
#define FOR(a, b, c, d) for (int(a) = (b); (a) < (c); (a) = (a) + (d))
typedef vector<int> vi;
typedef vector<vi> vvi;
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define ff first
#define ss second
#define PI 3.141592653589793238462
#define set_bits __builtin_popcountll
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
typedef pair<int, int> pii;
typedef pair<long, long> pll;
typedef pair<int, pair<int, int>> ppi;
// typedef tree<pair<int, int>, null_type, less<pair<int, int>>, rb_tree_tag, tree_order_statistics_node_update > pbds; // find_by_order, order_of_key
#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(int 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(deque<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(unordered_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 << "]";
}
template <class T, class V>
void _print(unordered_map<T, V> v)
{
    cerr << "[ ";
    for (auto i : v)
    {
        _print(i);
        cerr << " ";
    }
    cerr << "]";
}

bool is_prime(ll n)
{
    if (n <= 1)
        return false;
    if (n <= 3)
        return true;
    if (n % 2 == 0 || n % 3 == 0)
        return false;
    for (int i = 5; i * i <= n; i = i + 6)
        if (n % i == 0 || n % (i + 2) == 0)
            return false;
    return true;
}

const ll M = 1e9 + 7;
int power(ll a, ll b)
{
    int ans = 1;
    while (b)
    {
        if (b & 1)
            ans = (ans * 1ll * a) % M;
        a = (a * 1ll * a) % M;
        b >>= 1;
    }
    return ans;
}

void solve()
{
    int n;
    cin >> n;
    vi a(n);
    FOR(i, 0, n, 1)
    cin >> a[i];
    int i = 0, j = 0;
    map<int, int> mp;
    int mx_len = 0;
    while (j < n)
    {
        mp[a[j]]++;
        if (mp.size() == j - i + 1)
        {
            mx_len = max(mx_len, j - i + 1);
        }
        else
        {
            while (i < n && mp.size() != j - i + 1)
            {
                mp[a[i]]--;
                if (mp[a[i]] == 0)
                    mp.erase(a[i]);
                i++;
            }
        }
        j++;
    }
    cout << mx_len << endl;
}
int main()
{
    fastio();

#ifndef ONLINE_JUDGE
    freopen("Error.txt", "w", stderr);

#endif

    solve();
    return 0;
}