Submission #348509

#	Time	Username	Problem	Language	Result	Execution time	Memory
348509		juggernaut	Highway Tolls (IOI18_highway)	C++14	12 / 100	198 ms	13424 KiB

highway

#include"highway.h"
#include<bits/stdc++.h>
#ifndef EVAL
#include"grader.cpp"
#endif
using namespace std;
vector<pair<int,int>>g[90005];
vector<int>grp[90005];
int id[90005],mx,up[90005];
long long pivot;
void dfs(int v,int p,int depth){
    mx=max(mx,depth);
    grp[depth].push_back(id[v]);
    for(auto to:g[v])if(to.first!=p){
        id[to.first]=to.second;
        up[to.second]=to.first;
        dfs(to.first,v,depth+1);
    }
}
void find_pair(int n,vector<int>x,vector<int>y,int a,int b){
    for(int i=0;i<n-1;i++){
        g[x[i]].push_back({y[i],i});
        g[y[i]].push_back({x[i],i});
    }
    vector<int>v(n-1,0);
    pivot=ask(v);
    dfs(0,0,0);
    int l=1,r=mx;
    while(l<r){
        //cout<<l<<"_"<<r;
        int mid=(l+r+1)>>1;
        vector<int>v(n-1,0);
        //cout<<"_"<<mid<<"\n";
        for(int i=mid;i<=mx;i++){
            //cout<<"DEPTH:"<<i;
            for(auto to:grp[i]){
                //cout<<" "<<to;
                v[to]=1;
            }
            //cout<<endl;
        }
        //cout<<"QUERY:";
        //for(auto to:v)cout<<to;
        //cout<<" "<<ask(v)<<endl;
        if(ask(v)!=pivot)l=mid;
        else r=mid-1;
    }
    int uid=l;
    //cout<<uid<<endl;
    l=0,r=grp[uid].size()-1;
    while(l<r){
        int mid=(l+r)>>1;
        vector<int>v(n-1,0);
        for(int i=l;i<=mid;i++)v[grp[uid][i]]=1;
        if(ask(v)!=pivot)r=mid;
        else l=mid+1;
    }
    int s=up[grp[uid][l]];



    answer(0,s);
}
/*
5 4 1 2 0 4
0 1
0 2
1 3
1 4
*/

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