Submission #720419

#	Time	Username	Problem	Language	Result	Execution time	Memory
720419		bin9638	Highway Tolls (IOI18_highway)	C++17	7 / 100	259 ms	29936 KiB

highway

#include <bits/stdc++.h>

#ifndef SKY
#include "highway.h"
#endif // SKY

using namespace std;

#define N 200010
#define ll long long
#define fs first
#define sc second
#define ii pair<int,int>
#define pb push_back

int times,ktr[N],root[2],cha[N][21],n,m,depth[N],par_id[N];
ll A,B;
ii canh[N],cnt[N];
vector<ii>g[N],ke[N];
queue<int>dq;

#ifdef SKY
int S_ans,T_ans;

void answer(int s,int t)
{
    cout<<s<<" "<<t<<endl;
}

ll dis[55][55];

ll ask(vector<int>w)
{
    memset(dis,0x3f3f,sizeof(dis));
    for(int i=0;i<m;i++)
        dis[canh[i].fs][canh[i].sc]=dis[canh[i].sc][canh[i].fs]=(w[i]==0 ? A : B);
    for(int k=0;k<n;k++)
        for(int i=0;i<n;i++)
            for(int j=0;j<n;j++)
                dis[i][j]=min(dis[i][j],dis[i][k]+dis[k][j]);
    return dis[S_ans][T_ans];
}
#endif // SKY

int query;
ll my_ask(vector<int>w)
{
  //  assert(w.size()==m);
    //assert(++query<=50);
    return ask(w);
}

void DFS(int u,int p)
{
    cnt[u].fs=++times;
    for(auto v:g[u])
        if(v.fs!=p)
        {
            par_id[v.fs]=v.sc;
            depth[v.fs]=depth[u]+1;
            cha[v.fs][0]=u;
            DFS(v.fs,u);
        }
    cnt[u].sc=times;
}

bool tren(int u,int v)
{
    return (cnt[u].fs<=cnt[v].fs&&cnt[u].sc>=cnt[v].sc);
}

bool SS(const int&u,const int&v)
{
    return depth[u]<depth[v];
}

int solve(int id,ll val,int cs)
{
    vector<int>s;
    for(int i=0;i<n;i++)
        if(i!=root[0]&&i!=root[1]&&tren(root[id],i))
            s.pb(i);
    sort(s.begin(),s.end(),SS);
   // cout<<id<<endl;
    //for(auto u:s)cout<<u<<" ";cout<<endl;
    int res=root[id],l=0,r=s.size()-1;
    while(l<=r)
    {
        int mid=(l+r)/2;
        vector<int>hoi(m,1);
        hoi[cs]=0;
        for(int i=0;i<n;i++)
            if(i!=root[0]&&i!=root[1]&&!tren(root[id],i))
                hoi[par_id[i]]=0;
        for(int i=0;i<=mid;i++)
            hoi[par_id[s[i]]]=0;
       // cout<<my_ask(hoi)<<endl;
        if(my_ask(hoi)==val)
        {
            res=s[mid];
            r=mid-1;
        }else
            l=mid+1;
    }
    return res;
}

void find_pair(int cc, vector<int> canh_fs, vector<int> canh_sc, int AAA, int BBB)
{
    n=cc;
    m=canh_fs.size();
    A=AAA;
    B=BBB;
    for(int i=0;i<m;i++)
    {
        canh[i]={canh_fs[i],canh_sc[i]};
        ke[canh[i].fs].pb({canh[i].sc,i});
        ke[canh[i].sc].pb({canh[i].fs,i});
    }
    ll val=my_ask(vector<int>(m,0));
    vector<int>s;
    for(int i=0;i<m;i++)
        s.pb(i);
    while(s.size()>1)
    {
        vector<int>L,R;
        for(int i=0;i<s.size();i++)
            if(i*2<s.size())
                L.pb(s[i]);
                    else R.pb(s[i]);
        vector<int>hoi(m,0);
        for(int i=0;i<=L.back();i++)
            hoi[i]=1;
        if(my_ask(hoi)!=val)
                s=L;
                    else s=R;
    }
    //cout<<canh[s[0]].fs<<" "<<canh[s[0]].sc<<endl;
    root[0]=canh[s[0]].fs;
    root[1]=canh[s[0]].sc;
    //cout<<root[0]<<" "<<root[1]<<endl;
    queue<int>dq;
    ktr[root[0]]=ktr[root[1]]=1;
    dq.push(root[0]);
    dq.push(root[1]);
    while(!dq.empty())
    {
        int u=dq.front();
        dq.pop();
        for(auto v:ke[u])
            if(ktr[v.fs]==0)
            {
                ktr[v.fs]=1;
                dq.push(v.fs);
                g[u].pb(v);
               // cout<<u<<" "<<v.fs<<endl;
            }
    }
    DFS(root[0],-1);
    DFS(root[1],-1);
    answer(solve(0,val,s[0]),solve(1,val,s[0]));
}

#ifdef SKY
int main()
{
    freopen("A.inp","r",stdin);
    freopen("A.out","w",stdout);
    ios::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
    srand(time(0));
    int n,m,A,B;
    map<int,int>mp[110];
    cin>>n>>m>>S_ans>>T_ans>>A>>B;
    vector<int>u(m),v(m);
    for(int i=0;i<m;i++)
        cin>>u[i]>>v[i];
  /* for(int i=0;i<n-1;i++)
    {
        u[i]=i+1;
        v[i]=rand()%(i+1);
         mp[min(u[i],v[i])][max(u[i],v[i])]++;
    }
    for(int i=n-1;i<m;i++)
    {
        u[i]=rand()%n;
        do{
            v[i]=rand()%n;
        }while(u[i]==v[i]||mp[min(u[i],v[i])][max(u[i],v[i])]!=0);
        assert(u[i]!=v[i]);
        mp[min(u[i],v[i])][max(u[i],v[i])]++;
    }*/
  //  for(int i=0;i<m;i++)cout<<u[i]<<" "<<v[i]<<endl;
    find_pair(n,u,v,A,B);
    return 0;
}
#endif

Compilation message (stderr)

highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:127:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  127 |         for(int i=0;i<s.size();i++)
      |                     ~^~~~~~~~~
highway.cpp:128:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  128 |             if(i*2<s.size())
      |                ~~~^~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 7 / 7
• Subtask 3: 0 / 6
• Subtask 4: 0 / 33
• Subtask 5: 0 / 18
• Subtask 6: 0 / 31