Submission #204943

#TimeUsernameProblemLanguageResultExecution timeMemory
204943oolimryCircle selection (APIO18_circle_selection)C++14
100 / 100
1034 ms49800 KiB
#include <bits/stdc++.h>
 
using namespace std; 
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];

inline long long ii(long long a, long long b){
	return a * (1LL << 32LL) + b;
}
 
unordered_map<long long, 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 << " ";
}
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