Submission #983985

#	Time	Username	Problem	Language	Result	Execution time	Memory
983985		Kenjikrab	Sequence (APIO23_sequence)	C++17	20 / 100	793 ms	67932 KiB

sequence

#include "sequence.h"
#include<bits/stdc++.h>
#define pii pair<int,int>
#define fi first
#define se second
using namespace std;
int const n_max=5e5+10;

struct Node{
  int sum;
  int mn;
  int mx;
  Node():sum(0),mn(0),mx(0){}
  Node(int a):sum(a),mn(min(0,a)),mx(max(0,a)){}
  Node operator +(Node a)
  {
    Node ret;
    ret.sum=sum+a.sum;
    ret.mn=min(mn,sum+a.mn);
    ret.mx=max(mx,sum+a.mx);
    return ret;
  }
};
Node tree[4*n_max];
void upd(int idx,int l,int r,int p,int v)
{
  if(p<l||r<p)return;
  if(l==r)
  {
    tree[idx]=Node(v);
    return;
  }
  int mid=(l+r)>>1;
  if(p<=mid)upd(idx<<1,l,mid,p,v);
  else upd(idx<<1^1,mid+1,r,p,v);
  tree[idx]=tree[idx<<1]+tree[idx<<1^1];
}
Node qr(int idx,int l,int r,int ll,int rr)
{
  if(rr<l||r<ll)return Node();
  if(ll<=l&&r<=rr)return tree[idx];
  int mid=(l+r)>>1;
  return qr(idx<<1,l,mid,ll,rr)+qr(idx<<1^1,mid+1,r,ll,rr);
}
vector<int> A;
vector<int> pos[n_max];
int sequence(int N, vector<int> _A)
{
  A.push_back(0);
  for(int i=0;i<N;i++)A.push_back(_A[i]);
  for(int i=1;i<=N;i++)pos[i].push_back(0);
  for(int i=1;i<=N;i++)pos[A[i]].push_back(i),upd(1,1,N,i,1);
  for(int i=1;i<=N;i++)pos[i].push_back(N+1);
  int ans=0;
  for(int i=1;i<=N;i++)
  {
    for(auto it:pos[i])upd(1,1,N,it,0);
    for(auto it:pos[i-1])upd(1,1,N,it,-1);
    vector<pii> keep;
    int time=0;
    for(int j=1;j<pos[i].size();j++)
    {
      Node temp=qr(1,1,N,pos[i][j-1]+1,pos[i][j]-1);
      keep.push_back({time+temp.mn,time+temp.mx});
      time+=temp.sum;
    }
    for(int j=1;j<keep.size();j++)
    {
      int l=0,r=j;
      while(l<r)
      {
        int mid=(l+r)>>1;
        if(-j>keep[j].se-keep[mid].fi||keep[j].fi-keep[mid].se>j)l=mid+1;
        else r=mid;
      }
      ans=max(ans,j-l);
      keep[j]={min(keep[j].fi,keep[j-1].fi),max(keep[j].se,keep[j-1].se)};
    }
  }
  return ans;
}

Compilation message (stderr)

sequence.cpp: In function 'int sequence(int, std::vector<int>)':
sequence.cpp:61:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |     for(int j=1;j<pos[i].size();j++)
      |                 ~^~~~~~~~~~~~~~
sequence.cpp:67:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |     for(int j=1;j<keep.size();j++)
      |                 ~^~~~~~~~~~~~

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