Submission #75654

#	Time	Username	Problem	Language	Result	Execution time	Memory
75654		tmwilliamlin168	Circle selection (APIO18_circle_selection)	C++14	64 / 100	3037 ms	49676 KiB

circle_selection

#include <bits/stdc++.h>
using namespace std;

#define ll long long

const int mxN=3e5;
int n, p[mxN], a[mxN];
ll x[mxN], y[mxN], r[mxN];
unordered_map<ll, vector<int>> mp;
unordered_set<ll> s;

void rs(int k) {
	mp.clear();
	s.clear();
	for(int i=0; i<n; ++i) {
		if(a[i]==-1) {
			mp[x[i]>>k<<32|y[i]>>k].push_back(i);
			s.insert(x[i]>>k);
		}
	}
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	
	cin >> n;
	for(int i=0; i<n; ++i) {
		cin >> x[i] >> y[i] >> r[i];
		p[i]=i;
	}
	sort(p, p+n, [&](const int &a, const int &b) {
		return r[a]==r[b]?a<b:r[a]>r[b];
	});
	memset(a, -1, 4*n);
	for(int i=-1, k=30; i+1<n; --i, --k) {
		rs(k);
		while(++i<n&&r[p[i]]>=1<<(k-1)) {
			if(a[p[i]]!=-1)
				continue;
			for(ll b=(x[p[i]]>>k)-2; b<=(x[p[i]]>>k)+2; ++b) {
				if(s.find(b)==s.end())
					continue;
				for(ll c=(y[p[i]]>>k)-2; c<=(y[p[i]]>>k)+2; ++c) {
					auto mf=mp.find(b<<32|c);
					if(mf==mp.end())
						continue;
					int ns=0;
					vector<int> &v=mf->second;
					for(int j=0; j<v.size(); ++j) {
						ll dx=x[p[i]]-x[v[j]], dy=y[p[i]]-y[v[j]], rs=r[p[i]]+r[v[j]];
						if(dx*dx+dy*dy<=rs*rs)
							a[v[j]]=p[i];
						else
							v[ns++]=v[j];
					}
					v.resize(ns);
				}
			}
		}
	}
	for(int i=0; i<n; ++i)
		cout << a[i]+1 << " ";
}

Compilation message (stderr)

circle_selection.cpp: In function 'int main()':
circle_selection.cpp:50:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
      for(int j=0; j<v.size(); ++j) {
                   ~^~~~~~~~~

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