Submission #719738

#	Time	Username	Problem	Language	Result	Execution time	Memory
719738		bin9638	Highway Tolls (IOI18_highway)	C++17	51 / 100	229 ms	262144 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,cha[N][21],n,m,depth[N],par_id[N];
ll A,B;
ii canh[N],cnt[N];
vector<ii>g[N];

#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(++query<=51);
    return ask(w);
}

ll get(vector<int>s)
{
    vector<int>w(m,0);
    for(auto u:s)
        w[par_id[u]]=1;
    return my_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);
}

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]};
        g[canh[i].fs].pb({canh[i].sc,i});
        g[canh[i].sc].pb({canh[i].fs,i});
    }
    vector<int>s(m,0);
    ll val=my_ask(s);
    memset(par_id,-1,sizeof(par_id));
    DFS(0,-1);
    int sau=-1,l=1,r=*max_element(depth,depth+n);
    while(l<=r)
    {
        int mid=(l+r)/2;
        vector<int>hoi(n-1,1);
        for(int i=1;i<n;i++)
            if(depth[i]<mid)
                hoi[par_id[i]]=0;
        if(val!=my_ask(hoi))
        {
            sau=mid;
            l=mid+1;
        }else
            r=mid-1;
    }
    s.clear();
    for(int i=1;i<n;i++)
        if(depth[i]==sau)
            s.pb(i);
    //cout<<s.size()<<endl;
    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]);
        if(get(L)!=val)
            s=L;
                else s=R;
    }
    int u=s[0],lca=u;
    {
        vector<int>hoi(m,0);
        int p=u;
        while(p!=0)
        {
            hoi[par_id[p]]=1;
            p=cha[p][0];
        }
        for(int i=(my_ask(hoi)-val)/(B-A);i>=1;i--)
            lca=cha[lca][0];
    }
    sau=depth[lca]+((my_ask(vector<int>(m,1))-val)/(B-A)-(depth[u]-depth[lca]));
   // cout<<u<<" "<<lca<<" "<<sau<<endl;
    if(sau==depth[lca])
    {
        answer(u,lca);
        return;
    }
    s.clear();
    for(int i=0;i<n;i++)
        if(depth[i]==sau&&!tren(i,u))
                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]);
        if(get(L)!=val)
            s=L;
                else s=R;
    }
    answer(s[0],u);
}

#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);
    int n,m,A,B;
    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];
    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:117:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  117 |         for(int i=0;i<s.size();i++)
      |                     ~^~~~~~~~~
highway.cpp:118:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  118 |             if(i*2<s.size())
      |                ~~~^~~~~~~~~
highway.cpp:151:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  151 |         for(int i=0;i<s.size();i++)
      |                     ~^~~~~~~~~
highway.cpp:152:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  152 |             if(i*2<s.size())
      |                ~~~^~~~~~~~~

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