Submission #399797

#	Time	Username	Problem	Language	Result	Execution time	Memory
399797		my99n	Circle selection (APIO18_circle_selection)	C++14	0 / 100	538 ms	36472 KiB

circle_selection

#include<bits/stdc++.h>
using namespace std;
#define x first
#define y second
typedef pair<long long,long long> point;

struct A {
  long long x, y, r;
  int i;
  bool operator < (const A & o) const {
    if (x == o.x) return i < o.i;
    return x < o.x;
  }
} cir[300100];

set<A> s;

bool compare (A & a, A & b) {
  if (a.r == b.r) return a.i < b.i;
  return a.r > b.r;
}

int ans[300100];

long long dis (point i, point j) {
  long long temp = ((i.x-j.x) * (i.x-j.x)) + ((i.y-j.y) * (i.y-j.y));
  return temp;
}

bool intersect (A i, A j) {
  // cerr << dis({i.x, i.y}, {j.x, j.y}) << ' ' << (i.r+j.r) << endl;
  return (dis({i.x, i.y}, {j.x, j.y}) <= (i.r+j.r)*(i.r+j.r));
}

int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n; cin >> n;
  for (int i = 1; i <= n; i++) {
    long long x, y, r; cin >> x >> y >> r;
    cir[i] = {x, y, r, i};
    s.insert({x, y, r, i});
  }
  sort(cir+1, cir+1+n, compare);

  // cerr << "here" << endl;

  // for (int i = 1; i <= n; i++) {
  //   auto a = s.lower_bound(cir[i]);
  //   assert(a->i == cir[i].i);
  // }

  for (int i = 1; i <= n; i++) {
    int ind = cir[i].i;
    if (ans[ind]) continue;
    auto a = s.lower_bound(cir[i]);
    assert(a->i == cir[i].i);
    // cerr << a->i << endl;
    if (a != s.begin()) {
      auto x = prev(a);
      // cerr << "? " << x->i << endl;
      while (x != s.begin()) {
        if (!intersect(*x, cir[i])) break;
        ans[x->i] = ind;
        auto temp = x--;
        s.erase(temp);
      }
      if (x == s.begin() and intersect(*x, cir[i])) {
        ans[x->i] = ind;
        auto temp = x;
        s.erase(temp);
      }
    }
    auto x = a;
    while (x != s.end()) {
      if (!intersect(*x, cir[i])) break;
      ans[x->i] = ind;
      auto temp = x++;
      s.erase(temp);
    }
  }

  for (int i = 1; i <= n; i++) {
    cout << ans[i] << ' ';
  } cout << endl;
  return 0;
}
/*
11 
9 9 2
13 2 1
11 8 2
3 3 2
3 12 1
12 14 1
9 8 5
2 8 2
5 2 1
14 4 2
14 14 1
*/

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