Submission #387637

#	Time	Username	Problem	Language	Result	Execution time	Memory
387637		milleniumEeee	Circle selection (APIO18_circle_selection)	C++17	7 / 100	282 ms	34628 KiB

circle_selection

#include <bits/stdc++.h>
#define fastInp ios_base::sync_with_stdio(0); cin.tie(0);
#define pii pair<int, int>
#define fr first
#define sc second
#define pb push_back
#define szof(s) (int)s.size()
#define all(s) s.begin(), s.end()
#define mk make_pair
#define int long long
using namespace std;

const int MAXN = (int)3e5 + 5;

int n;

int x[MAXN];
int y[MAXN];
int rad[MAXN];

vector <int> g[MAXN];

double get_dist(int i, int j) {
	return (x[i] - x[j]) * (x[i] - x[j]) + (y[i] - y[j]) * (y[i] - y[j]);
}

bool intersect(int i, int j) {
	return (get_dist(i, j) <= (rad[i] + rad[j]) * (rad[i] + rad[j]));
}

int ans[MAXN];

vector <int> pos;

void subtask1() {
	for (int i = 0; i < n; i++) {
		pos.pb(i);
	}
	sort(all(pos), [&](int A, int B) {
		if (rad[A] != rad[B]) {
			return rad[A] > rad[B];
		} else {
			return A < B;
		}
	});
	memset(ans, -1, sizeof(ans));
	for (int el : pos) {
		if (ans[el] == -1) {
			ans[el] = el;
			for (int i = 0; i < n; i++) {
				if (ans[i] == -1 && intersect(i, el)) {
					ans[i] = el;
				}
			}
		}
	}
	for (int i = 0; i < n; i++) {
		cout << ans[i] + 1 << " ";
	}
	exit(0);
}

struct node {
	int x, y, rad;
	int ind;
	node () {
		
	}
	node (int x_, int y_, int rad_, int ind_) {
		x = x_;
		y = y_;
		rad = rad_;
		ind = ind_;
	}
	const bool operator < (const node &other) {
		return x < other.x;
	}
};

signed main() {
	fastInp;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> x[i] >> y[i] >> rad[i];
	}
	if (n <= 5000) {
		subtask1();
	}
	else {
		vector <node> vec;
		for (int i = 0; i < n; i++) {
			vec.pb(node(x[i], y[i], rad[i], i));
		}
		sort(all(vec));
		for (int i = 0; i < n; i++) {
			pos.pb(i);
		}
		sort(all(pos), [&](int A, int B) {
			if (vec[A].rad != vec[B].rad) {
				return vec[A].rad > vec[B].rad;
			} else {
				return vec[A].ind < vec[B].ind;
			}
		});
		memset(ans, -1, sizeof(ans));
		vector <int> block(1000, -1);
		int S = sqrt(n);
		if (S * S < n) {
			S++;
		}
		for (int order : pos) {
			if (ans[vec[order].ind] != -1) {
				continue;
			}
			if (block[order / S] != -1) {
				continue;
			}
			int x = vec[order].x;
			int rad = vec[order].rad;
			int lp = x - rad;
			int rp = x + rad;
			int l = -1, r = order;
			int lft, rgt;
			while (r - l > 1) {
				int mid = (l + r) >> 1;
				if (vec[mid].x >= lp) {
					r = mid;
				} else {
					l = mid;
				}
			}
			lft = r;
			l = order, r = n; // 0-index
			while (r - l > 1) {
				int mid = (l + r) >> 1;
				if (vec[mid].x <= rp) {
					l = mid;
				} else {
					r = mid;
				}
			}
			rgt = l;
			// update in sqrt decomposition 
			if (lft % S != 0) {
				for (int j = lft; j < (lft / S + 1) * S; j++) {
					if (block[j / S] != -1 || ans[vec[j].ind] != -1) {
						continue;
					}
					ans[vec[j].ind] = vec[order].ind;
				}
			}
			if ((rgt + 1) % S != 0) {
				for (int j = rgt; j >= (rgt / S) * S; j--) {
					if (block[j / S] != -1 || ans[vec[j].ind] != -1) {
						continue;
					}
					ans[vec[j].ind] = vec[order].ind;
				}
			}
			int l_block = (lft % S != 0 ? lft / S + 1 : lft / S);
			int r_block = ((rgt + 1) % S != 0 ? rgt / S - 1 : rgt / S);
			for (int j = l_block; j <= r_block; j++) {
				if (block[j] == -1) {
					block[j] = vec[order].ind;
				}
			}
		}
		for (int i = 0; i < n; i++) {
			if (ans[i] != -1) {
				cout << ans[i] + 1 << " ";
			} else {
				cout << block[i / S] + 1 << " ";
			}
		}
	}
}
/*
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: 0 / 12
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 30
• Subtask 6: 0 / 13