Submission #258974

#	Time	Username	Problem	Language	Result	Execution time	Memory
258974		amoo_safar	Circle selection (APIO18_circle_selection)	C++17	100 / 100	777 ms	28752 KiB

circle_selection

// Null
#include <bits/stdc++.h>

#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
 
#define pb push_back
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " : " << x << '\n'
 
using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef string str;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;

const ll Mod = 1000000007LL;
const int N = 3e5 + 10;
const int Inf = 2e9;

int n, x[N], y[N], r[N];
int mk[N];

vector<pii> V[N];
vector<int> U, X, Y;

void Build(int L){
	for(int i = 0; i < (int) U.size(); i++) V[i].clear();
	U.clear();

	for(int i : X){
		if(mk[i]) continue;
		U.pb(x[i] / L);
	}
	//sort(all(U));
	U.resize(unique(all(U)) - U.begin() );
	for(int i : Y)
		if(!mk[i])
			V[lower_bound(all(U), x[i] / L) - U.begin()].pb({y[i] / L, i});
	for(int i = 0; i < (int) U.size(); i++)
		sort(all(V[i]));
}

int main(){
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin >> n;
	for(int i = 1; i <= n; i++){
		cin >> x[i] >> y[i] >> r[i];
		X.pb(i);
		Y.pb(i);
	}
	vector<int> I(n); iota(all(I), 1);
	sort(all(I), [&](int i, int j){
		return (r[i] == r[j] ? i < j : r[i] > r[j]);
	});
	sort(all(X), [&](int i, int j){
		return x[i] < x[j];
	});
	sort(all(Y), [&](int i, int j){
		return y[i] < y[j];
	});

	int L = r[I[0]];
	Build(L);
	for(auto id : I){
		if(mk[id]) continue;
		if(L >= 4*r[id]) Build(L = r[id]);

		int i = x[id] / L;
		int j = y[id] / L;

		int nei;
		for(int pos = lower_bound(all(U), i - 2) - U.begin(); pos < (int) U.size() && U[pos] <= i + 2; pos ++){

			for(int posj = lower_bound(all(V[pos]), pii(j - 2, -1)) - V[pos].begin(); posj < (int) V[pos].size() && V[pos][posj].F <= j + 2; posj ++){
				nei = V[pos][posj].S;
				if(mk[nei]) continue;
				if(1ll*(x[id] - x[nei])*(x[id] - x[nei]) + 1ll*(y[id] - y[nei])*(y[id] - y[nei]) <= 1ll*(r[id] + r[nei])*(r[id] + r[nei]) ){
					mk[nei] = id;
				}
			}
		}
	}
	
	for(int i = 1; i <= n; i++) cout << mk[i] << ' ';
	cout << '\n';
	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: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 15 / 15
• Subtask 4: 23 / 23
• Subtask 5: 30 / 30
• Subtask 6: 13 / 13