Submission #932104

#	Time	Username	Problem	Language	Result	Execution time	Memory
932104		Edu175	Sequence (APIO23_sequence)	C++17	11 / 100	2079 ms	842092 KiB

sequence

#include "sequence.h"
#include <bits/stdc++.h>
#define pb push_back
#define fst first
#define snd second
#define fore(i,a,b) for(ll i=a,apio=b;i<apio;i++)
#define SZ(x) ((int)x.size())
#define ALL(x) x.begin(),x.end()
#define mset(a,v) memset((a),(v),sizeof(a))
#define imp(v) for(auto slkdh:v)cout<<slkdh<<" ";cout<<"\n"
using namespace std;
typedef int ll;
typedef pair<ll,ll> ii;
#pragma GCC optimize("Ofast") // may lead to precision errors

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
const ll C=5e5,MAXN=2*C+5;

unordered_map<ll,ll> ft[MAXN+1];
void upd(ll p, ll q, ll v){
	p+=C,q+=C;
	p=MAXN-1-p; v-=C;
	//cout<<"upd "<<p<<","<<q<<" "<<-v<<"\n";
	for(ll i=p+1;i<=MAXN;i+=i&-i)
	for(ll j=q+1;j<=MAXN;j+=j&-j){
		ll &r=ft[i][j];
		r=min(r,v);
	}
}
ll query(ll p, ll q){
	p+=C,q+=C;
	p=MAXN-1-p;
	//cout<<"query "<<p<<","<<q<<"\n";
	ll res=0;
	for(ll i=p+1;i;i-=i&-i)
	for(ll j=q+1;j;j-=j&-j){
		res=min(res,ft[i][j]);
	}
	//cout<<res<<" res\n";
	return res+C;
}

int sequence(int N, std::vector<int> A) {
	ll n=N;
	vector<ll>a(n);
	fore(i,0,n)a[i]=A[i]-1;
	vector<ll>pos[n];
	fore(i,0,n)pos[a[i]].pb(i);
	vector<ll>s(n);
	fore(i,0,n)s[i]=1;
	ll res=0;
	fore(i,0,n)if(SZ(pos[i])){
		//cout<<"\nin"<<i<<":\n";
		for(auto j:pos[i])s[j]=0;
		//imp(s);
		fore(j,0,MAXN)ft[j].clear();
		upd(0,0,0);
		ll sum=0,rew=0;
		fore(j,0,n){
			sum+=s[j],rew+=a[j]==i;
			ll p=sum-rew,q=sum+rew;
			res=max(res,rew-query(p,q));
			upd(p,q,rew);
			//cout<<j<<": "<<sum<<" "<<rew<<"\n";
			//cout<<"add "<<p<<","<<q<<" "<<rew<<"\n";
			//cout<<res<<"\n\n";
		}
		//cout<<res<<"\n";
		for(auto j:pos[i])s[j]=-1;
	}
	return res;
}

• Subtask 1: 11 / 11
• Subtask 2: 0 / 17
• Subtask 3: 0 / 7
• Subtask 4: 0 / 12
• Subtask 5: 0 / 13
• Subtask 6: 0 / 22
• Subtask 7: 0 / 18