Submission #750400

#	Time	Username	Problem	Language	Result	Execution time	Memory
750400		jamezzz	Sequence (APIO23_sequence)	C++17	82 / 100	2096 ms	137392 KiB

sequence

#include "sequence.h"
#include <bits/stdc++.h>
using namespace std;

#define pf printf
#define pb push_back

#define maxn 500005

struct node{
	int s,e,m,mn,mx,lz;node *l,*r;
	node(int _s,int _e){
		s=_s,e=_e,m=(s+e)>>1,mn=0,mx=0,lz=0;
		if(s!=e)l=new node(s,m),r=new node(m+1,e);
	}
	void ppo(){
		mn+=lz,mx+=lz;
		if(lz&&s!=e){
			l->lz+=lz;
			r->lz+=lz;
		}
		lz=0;
	}
	void up(int x,int y,int nv){
		if(s==x&&e==y){lz+=nv;return;}
		if(y<=m)l->up(x,y,nv);
		else if(x>m)r->up(x,y,nv);
		else l->up(x,m,nv),r->up(m+1,y,nv);
		l->ppo(),r->ppo();
		mn=min(l->mn,r->mn);
		mx=max(l->mx,r->mx);
	}
	int qmx(int x,int y){
		if(s==x&&e==y)return mx+lz;
		ppo();
		if(y<=m)return l->qmx(x,y);
		if(x>m)return r->qmx(x,y);
		return max(l->qmx(x,m),r->qmx(m+1,y));
	}
	int qmn(int x,int y){
		if(s==x&&e==y)return mn+lz;
		ppo();
		if(y<=m)return l->qmn(x,y);
		if(x>m)return r->qmn(x,y);
		return min(l->qmn(x,m),r->qmn(m+1,y));
	}
}*prt,*srt;

int pmn[maxn],pmx[maxn],smn[maxn],smx[maxn],tot[maxn][2];
vector<int> v[maxn];

//a range is valid if sum(>=x)-sum(<x)>=0 --> find min: == x value 1
//and sum(>x)-sum(<=x)<=0 --> find max: == x value -1

inline bool check(int i,int l,int r){
	return (tot[i][0]-pmn[l]-smn[r]>=0)&&(tot[i][1]-pmx[l]-smx[r]<=0);
}

int sequence(int N,vector<int> A){
	prt=new node(0,N+1);
	srt=new node(0,N+1);
	for(int i=0;i<N;++i){
		v[A[i]].pb(i+1);
		prt->up(i+1,N+1,1);
		srt->up(0,i+1,1);
	}
	for(int i=1;i<=N;++i){
		for(int x:v[i]){
			pmn[x]=prt->qmn(0,x-1);
			smn[x]=srt->qmn(x+1,N+1);
		}
		tot[i][0]=prt->qmx(N,N);
		for(int x:v[i]){
			prt->up(x,N+1,-2);
			srt->up(0,x,-2);
		}
		tot[i][1]=prt->qmx(N,N);
		for(int x:v[i]){
			pmx[x]=prt->qmx(0,x-1);
			smx[x]=srt->qmx(x+1,N+1);
		}
	}
	int ans=0;
	for(int i=1;i<=N;++i){
		if(v[i].empty())continue;
		int l=0,r=0;
		while(r<v[i].size()){
			assert(l<=r);
			if(check(i,v[i][l],v[i][r])){
				ans=max(ans,r-l+1);
				++r;
			}
			else ++l;
		}
	}
	return ans;
}

Compilation message (stderr)

sequence.cpp: In function 'int sequence(int, std::vector<int>)':
sequence.cpp:87:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   87 |   while(r<v[i].size()){
      |         ~^~~~~~~~~~~~

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