Submission #204934

#	Time	Username	Problem	Language	Result	Execution time	Memory
204934		oolimry	Circle selection (APIO18_circle_selection)	C++14	12 / 100	1749 ms	47456 KiB

circle_selection

#include <bits/stdc++.h>

using namespace std;
typedef pair<long long, long long> ii;

int n; 

struct Circle{
	long long x, y, r, id;
} arr[300005];

bool intersect(Circle a, Circle b){
	return (a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y) <= (a.r + b.r) * (a.r + b.r);
}

long long ans[300005];
bool used[300005];

struct pair_hash{
	std::size_t operator () (ii const &pair) const{
		return pair.first ^ pair.second;
	}
};

map<ii, vector<int> > GRID;
long long gridSize = 1LL << 61LL;

void buildGrid(long long newGridSize){
	gridSize = newGridSize;
	GRID.clear();
	
	for(int i = 0;i < n;i++){
		if(!used[i]){
			long long xSquare = arr[i].x / gridSize;
			long long ySquare = arr[i].y / gridSize;
			GRID[ii(xSquare,ySquare)].push_back(i);
		}
	}
}

bool comp(Circle a, Circle b){
	if(a.r == b.r) return a.id < b.id;
	else return a.r > b.r;
}

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	
	cin >> n;
	fill(ans, ans + n, -1);
	
	for(int i = 0;i < n;i++){
		long long x, y, r; cin >> x >> y >> r;
		x += (1LL << 30LL); y += (1LL << 30LL);
		arr[i] = {x, y, r, i};
	}
	
	sort(arr,arr+n,comp);
	
	for(int i = 0;i < n;i++){
		Circle C = arr[i];
		
		if(used[i]) continue;
		
		if(gridSize > 2LL * C.r){
			buildGrid(C.r);
		}
		
		long long xSquare = C.x / gridSize;
		long long ySquare = C.y / gridSize;
		
		for(long long x = xSquare - 2;x <= xSquare + 2;x++){
			for(long long y = ySquare - 2;y < ySquare + 2;y++){
				
				if(GRID.find(ii(x,y)) == GRID.end()) continue;
				vector<int> &points = GRID[ii(x,y)];
				
				for(int p = 0;p < (int) points.size();p++){
					if(intersect(arr[points[p]], C)){
						ans[arr[points[p]].id] = C.id;
						used[points[p]] = true;
												
						points[p] = points.back();
						points.pop_back();
						p--;
					}
				}
			}
		}
	}
	
	for(int i = 0;i < n;i++) cout << ans[i] + 1 << " ";
}

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