cses_1141.cxx

#include <iostream>
#include <algorithm>
#include <array>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <utility>
#include <bitset>
#include <unordered_map>
#include <unordered_set>
#include <stack>
#include <bitset>
#include <cmath>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <cstdint>
#pragma GCC diagnostic ignored "-Wunused-parameter"
#pragma GCC diagnostic ignored "-Wunused-variable"
#pragma GCC diagnostic ignored "-Wunused-result"
#pragma GCC diagnostic ignored "-Wpragmas"
#pragma GCC diagnostic ignored "-Wunused-function"
#pragma GCC diagnostic ignored "-Wunused-but-set-variable"
#pragma GCC diagnostic ignored "-Wunused-but-set-parameter"
#pragma GCC diagnostic ignored "-Wwrite-strings"
#pragma GCC diagnostic ignored "-Wunused-local-typedefs"
#pragma GCC diagnostic ignored "-Wunused-but-set-label"
#pragma GCC diagnostic ignored "-Wunused-label"
#pragma GCC diagnostic ignored "-Wmissing-field-initializers"
#pragma GCC diagnostic ignored "-Wmissing-braces"
#pragma GCC diagnostic ignored "-Wmissing-declarations"
#pragma GCC diagnostic ignore "-Wmaybe-uninitialized"
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#pragma GCC optimize("Ofast", "unroll-loops")
#ifdef __linux__
#       include<unistd.h>
#endif
using namespace std;
using ll=long long;
using ull=unsigned long long;
using ld=long double;
using str=string;
#define TRUE 1
#define FALSE 0
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define eb emplace_back
#define RANGE(a,b) for(int i=a;i<=b;i++)
#define PI 3.14159265358979323846
#ifdef LOCAL_JUDGE_HOST
#   define __trace(x) cerr<<"["<<__LINE__<<"] "<<#x<<"@"<<&x<<"="<<x<<endl;
#else
#   define __trace(x)
#endif
namespace judge
{
        template<typename T>
        inline void partial_sum(vector<T> x)
        {
                partial_sum(all(x),x.begin());
        }

        inline void setIO(str name="")
        {
                ios_base::sync_with_stdio(false);
                cin.tie(nullptr);
                cout.tie(nullptr);
                if (!name.empty())
                {
                        freopen((name+".in").c_str(),"r",stdin);
                        freopen((name+".out").c_str(),"w",stdout);
                }
        }
        int gcd(int a,int b)
        {
                return a==0||a==b?b:b==0||b%a==0?a:a>b?gcd(b,a):gcd(a,b%a);
        }
        inline int low_bit(int x)
        {
                return x&(-x);
        }
#ifdef __linux__
        ostream& operator<<(ostream& os,const __int128_t& v)
        {
                if (!v)
                        os<<"0";
                __int128_t tmp=v<0?(os<<"-",-v):v;
                string s;
                while (tmp)
                {
                        s+='0'+(tmp%10);
                        tmp/=10;
                }
                return reverse(all(s)),os<<s;
        }
        ostream& operator<<(ostream& os,const __uint128_t& v)
        {
                if (!v)
                        os<<"0";
                __uint128_t tmp=v;
                string s;
                while (tmp)
                {
                        s+='0'+(tmp%10);
                        tmp/=10;
                }
                return reverse(all(s)),os<<s;
        }
#endif
};
using namespace judge;
namespace generics
{
        template<typename T>
        class Graph
        {
        public:
                struct Edge
                {
                        int from;
                        int to;
                        T weight;
                        Edge(int from,int to,T weight) :from(from),to(to),weight(weight)
                        {
                        }
                };
                vector<Edge> edges;
                vector<vector<int>> ver;
                int n;
                Graph(int n) :n(n)
                {
                        ver.resize(n);
                }
                virtual int addEdge(const Edge& edge)=0;
        };
        template<typename T>
        class UndirectedGraph :public Graph<T>
        {
        public:
                UndirectedGraph(int n) :Graph<T>(n)
                {
                }
                int addEdge(const typename Graph<T>::Edge& edge) override
                {
                        assert(0<=edge.from&&edge.from<Graph<T>::n&&0<=edge.to&&edge.to<Graph<T>::n);
                        int id=(int)Graph<T>::edges.size();
                        Graph<T>::ver[edge.from].pb(id);
                        Graph<T>::g[edge.to].pb(id);
                        Graph<T>::edges.pb(edge);
                        return id;
                }
        };
        template<typename T>
        class DirectedGraph :public Graph<T>
        {
        public:
                DirectedGraph(int n) :Graph<T>(n)
                {
                }
                int addEdge(const typename Graph<T>::Edge& edge) override
                {
                        assert(0<=edge.from&&edge.from<Graph<T>::n&&0<=edge.to&&edge.to<Graph<T>::n);
                        int id=(int)Graph<T>::edges.size();
                        Graph<T>::g[edge.from].pb(id);
                        Graph<T>::edges.pb(edge);
                        return id;
                }
        };
        struct UnionFind
        {
                vector<int> uf;
                int n;
                UnionFind(int n) :uf(n,-1),n(n)
                {
                }
                int find(int v)
                {
                        return uf[v]<0?v:uf[v]=find(uf[v]);
                }
                bool join(int v,int w)
                {
                        if ((v=find(v))==(w=find(w)))
                                return false;
                        if (uf[v]>uf[w])
                                ::swap(v,w);
                        uf[v]+=uf[w];
                        uf[w]=v;
                        n--;
                        return true;
                }
                bool connected(int v,int w)
                {
                        return find(v)==find(w);
                }
                int size(int v)
                {
                        return -uf[find(v)];
                }
        };
};
static const int MAX=2e5;
signed main()
{
        setIO();
        int n,k[MAX],ax=-1,ans;
        cin>>n;
        set<int> p;
        for(int i=0;i<n;i++)
                cin>>k[i];

        for(int i=0;i<n;i++)
        {
                while(ax<n-1&&!p.count(k[ax+1]))
                        p.insert(k[++ax]);
                ans=max(ans,ax-i+1);
                p.erase(k[i]);
        }
        cout<<ans;
        return 0;
}