Submission #971559

#	Time	Username	Problem	Language	Result	Execution time	Memory
971559		irmuun	Circle selection (APIO18_circle_selection)	C++17	19 / 100	790 ms	269900 KiB

circle_selection

#include<bits/stdc++.h>

using namespace std;

#define ll long long
#define pb push_back
#define ff first
#define ss second
#define all(s) s.begin(),s.end()
#define rall(s) s.rbegin(),s.rend()

const ll N=3e5+5;
ll n;
ll x[N],y[N],r[N];
vector<ll>adj[N],ans(N,0);
vector<bool>used(N,0);

ll dist(ll i,ll j){
    return abs(x[i]-x[j])*abs(x[i]-x[j])+abs(y[i]-y[j])*abs(y[i]-y[j]);
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    cin>>n;
    vector<pair<ll,ll>>v;
    bool Y=true;
    for(ll i=1;i<=n;i++){
        cin>>x[i]>>y[i]>>r[i];
        v.pb({-r[i],i});
        Y&=(y[i]==0);
    }
    sort(all(v));
    if(n<=5000){
        for(ll i=1;i<=n;i++){
            for(ll j=i+1;j<=n;j++){
                if(dist(i,j)<=(r[i]+r[j])*(r[i]+r[j])){
                    adj[i].pb(j);
                    adj[j].pb(i);
                }
            }
        }
        for(auto [R,i]:v){
            if(ans[i]>0) continue;
            ans[i]=i;
            for(ll j:adj[i]){
                if(ans[j]==0) ans[j]=i;
            }
        }
        for(ll i=1;i<=n;i++){
            cout<<ans[i]<<' ';
        }
        return 0;
    }
    if(Y){
        set<pair<ll,ll>>L,R;
        for(ll i=1;i<=n;i++){
            L.insert({x[i]-r[i],i});
            R.insert({x[i]+r[i],i});
        }
        vector<ll>del;
        for(auto [ra,i]:v){
            if(ans[i]>0) continue;
            del.clear();
            auto it=L.lower_bound({x[i]-r[i],0});
            while(it!=L.end()&&it->ff<=x[i]+r[i]){
                del.pb(it->ss);
                it++;
            }
            auto it1=R.lower_bound({x[i]-r[i],0});
            while(it1!=R.end()&&it1->ff<=x[i]+r[i]){
                del.pb(it1->ss);
                it1++;
            }
            for(auto j:del){
                if(ans[j]==0){
                    ans[j]=i;
                    L.erase({x[j]-r[j],j});
                    R.erase({x[j]+r[j],j});
                }
            }
        }
        for(ll i=1;i<=n;i++){
            cout<<ans[i]<<' ';
        }
        cout<<"\n";
        return 0;
    }
}

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 30
• Subtask 6: 0 / 13