제출 #965529

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
965529		FEDIKUS	통행료 (IOI18_highway)	C++17	100 / 100	298 ms	23004 KiB

highway

#include "highway.h"
#include<bits/stdc++.h>

using namespace std;
using ll = long long;

const int maxn=90010;

vector<pair<int,int> > g[maxn];
int intime[maxn];
bool posetio[maxn];
vector<int> nisu;
vector<pair<int,int> > g2[maxn];
vector<int> redosled;

void bfs(int n,int m,int prva,int poc1,int poc2){
  queue<int> bfs;
  bfs.push(poc1);
  bfs.push(poc2);
  posetio[poc1]=true;
  posetio[poc2]=true;
  redosled.push_back(prva);
  g2[poc1].push_back({poc2,prva});
  g2[poc2].push_back({poc1,prva});

  int t=0;
  set<int> jesu;
  jesu.emplace(prva);

  while(!bfs.empty()){
    int node=bfs.front();
    intime[node]=t++;
    bfs.pop();

    for(auto [u,ind]:g[node]){
      if(posetio[u]) continue;
      //if(ind<prva) continue;
      posetio[u]=true;
      bfs.push(u);

      g2[node].push_back({u,ind});
      g2[u].push_back({node,ind});

      redosled.push_back(ind);
      jesu.emplace(ind);
    }
  }
  for(int i=0;i<m;i++) if(jesu.find(i)==jesu.end()) nisu.push_back(i);
}

bool bio[maxn];
set<int> tren;
vector<int> red;

void dfs(int node){
  bio[node]=true;
  for(auto [u,ind]:g2[node]){
    if(bio[u]) continue;
    tren.emplace(ind);
    dfs(u);
  }
}

int uradi(int n,int m,ll bez,int prva,int poc1,int poc2,vector<int> &u,vector<int> &v){
  tren.clear();
  for(int i=0;i<n;i++) bio[i]=false;
  for(auto [u,ind]:g2[poc1]) if(u!=poc2) bio[u]=true;
  dfs(poc1);
  red.clear();
  for(int i:redosled) if(tren.find(i)!=tren.end()) red.push_back(i);

  int l=0;
  int r=int(red.size())-1; // ?
  int ret=-1;
  while(l<=r){
    int mid=l+(r-l)/2;

    vector<int> w(m,0);
    //fill(w.begin(),w.begin()+prva,1);
    for(int i:nisu) w[i]=1;
    for(int i=mid;i<int(red.size());i++){
      w[red[i]]=1;
    }
    if(ask(w)>bez){
      ret=mid;
      l=mid+1;
    }else r=mid-1;
  }

  if(ret==0) return poc2;

  if(intime[u[red[ret]]]>intime[v[red[ret]]]){
    return u[red[ret]];
  }else return v[red[ret]];
}

void find_pair(int n,vector<int> u,vector<int> v,int a,int b) {
  int m=u.size();
  int prva=0;
  int l=1,r=m;
  ll bez=ask(vector<int>(m,0));
  while(l<=r){
    int mid=l+(r-l)/2;
    vector<int> w(m,0);
    fill(w.begin(),w.begin()+mid,1);
    if(ask(w)>bez){
      prva=mid;
      r=mid-1;
    }else l=mid+1;
  }

  prva--;

  for(int i=0;i<m;i++){
    g[u[i]].push_back({v[i],i});
    g[v[i]].push_back({u[i],i});
  }

  bfs(n,m,prva,u[prva],v[prva]);

  int lik1=uradi(n,m,bez,prva,u[prva],v[prva],u,v);
  int lik2=uradi(n,m,bez,prva,v[prva],u[prva],u,v);

  //cout<<lik1<<" "<<lik2<<"\n";

  answer(lik1,lik2);
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 33 / 33
• Subtask 5: 18 / 18
• Subtask 6: 31 / 31