Submission #984699

#	Time	Username	Problem	Language	Result	Execution time	Memory
984699		huutuan	Circle selection (APIO18_circle_selection)	C++14	100 / 100	1925 ms	55192 KiB

circle_selection

#include<bits/stdc++.h>

using namespace std;

#define int long long

const int N=3e5+10;
int n;
pair<int, int> a[N];
int b[N], del[N];
map<pair<int, int>, vector<int>> mp;

bool check(int i, int j){
   return ((a[i].first-a[j].first)*(a[i].first-a[j].first)+(a[i].second-a[j].second)*(a[i].second-a[j].second))<=(b[i]+b[j])*(b[i]+b[j]);
}

int32_t main(){
   ios_base::sync_with_stdio(false);
   cin.tie(nullptr);
   int x=0;
   cin >> n;
   for (int i=1; i<=n; ++i){
      cin >> a[i].first >> a[i].second >> b[i];
      a[i].first+=1e9; a[i].second+=1e9;
      x=max(x, b[i]);
   }
   vector<int> v(n); iota(v.begin(), v.end(), 1);
   sort(v.begin(), v.end(), [&](int k, int l){
      return make_pair(b[k], -k)>make_pair(b[l], -l);
   });
   auto build=[&](){
      mp.clear();
      for (int i=1; i<=n; ++i) if (!del[i]){
         mp[{a[i].first/x, a[i].second/x}].push_back(i);
      }
   };
   build();
   for (int i:v){
      if (del[i]) continue;
      if (b[i]<=x/2){
         x/=2;
         build();
      }
      for (int j=a[i].first/x-2; j<=a[i].first/x+2; ++j){
         for (int k=a[i].second/x-2; k<=a[i].second/x+2; ++k){
            if (!mp.count({j, k})) continue;
            for (int l:mp[{j, k}]) if (!del[l] && check(i, l)) del[l]=i;
         }
      }
   }
   for (int i=1; i<=n; ++i) cout << del[i] << " \n"[i==n];
   return 0;
}

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