Submission #1168664

#	Time	Username	Problem	Language	Result	Execution time	Memory
1168664		rayan_bd	Sequence (APIO23_sequence)	C++20	0 / 100	692 ms	148368 KiB

sequence

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

const double INF = 5e18;
const int mxN = 5e5+100;

#define fi first
#define se second
#define all(v) v.begin(), v.end()

vector<int> seg[mxN*4];
vector<int> ar;

void build(int node,int start,int end){
	seg[node].clear();
	if(start==end){
		seg[node]={ar[start]};
		return;
	}
	int mid=start+(end-start)/2;
	build(node*2+1,start,mid);
	build(node*2+2,mid+1,end);
	merge(all(seg[node*2+1]),all(seg[node*2+2]),back_inserter(seg[node]));
}


int qry(int node,int start,int end,int l,int r,int k){
	if(start>r||end<l) return 0;
	if(start>=l&&end<=r) return upper_bound(all(seg[node]),k)-seg[node].begin();
	int mid=start+(end-start)/2;
	return qry(node*2+1,start,mid,l,r,k)+qry(node*2+2,mid+1,end,l,r,k);
}


int sequence(int N,vector<int> A){
	ar=A;
	for(int i=0;i<N*4+100;++i) seg[i].clear();
	build(0,0,N-1);
	map<int,pair<int,int>> mp;
	for(int i=0;i<N;++i){
		if(!mp.count(A[i])) mp[A[i]].fi=i;
		mp[A[i]].se=i;
	}
	int ans=1;
	for(auto it:A){
		int len=(mp[it].se-mp[it].fi+1);
		if(len==1) continue;
		if(len<=4) ans=2;
		if(len>=5){
			int pos=qry(0,0,N-1,mp[it].fi+1,mp[it].se-1,it)+1;
			if(len&1^1){
				if(pos==(len/2)) ans=2;
				if(pos==(len/2+1)) ans=2;
				if(++pos==(len/2)) ans=2;
				if(pos==(len/2+1)) ans=2;
			}else{
				if(pos==(len+1)/2) ans=2;
				else if(pos+1==(len+1)/2) ans=2;
			}
		}
	}



	return ans;
}

• Subtask 1: 0 / 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