Submission #851534

#	Time	Username	Problem	Language	Result	Execution time	Memory
851534		dlalswp25	Circle selection (APIO18_circle_selection)	C++17	19 / 100	689 ms	178256 KiB

circle_selection

#include <bits/stdc++.h>

using namespace std;
typedef pair<int, int> pii;

const int K = 2;

int N;
int X[303030];
int Y[303030];
int R[303030];
int XL[303030];
int XR[303030];
int ans[303030];
int cur;
char rr;

void rf(int &x) {
	x = 0;
	int sgn = 0;
	while (rr < 48 && rr != '-') rr = getchar();
	if (rr == '-') { sgn = 1; rr = getchar(); }
	while (47 < rr) { x = (x << 3) + (x << 1) + (rr & 15); rr = getchar(); }
	if (sgn) x = -x;
}

inline bool intersect(int i, int j) {
	long long dx = X[i] - X[j], dy = Y[i] - Y[j], r = R[i] + R[j];
	return dx * dx + dy * dy <= r * r;
}

inline void chk(int cand) {
	int &t = ans[cur];
	if (pii(R[cand], -cand) < pii(R[t], -t)) return;
	if (intersect(cur, cand)) t = cand;
}

struct SegTree {
	struct Node {
		set<pii> s;
	};

	int n, base;
	vector<Node> T;
	vector<int> L;

	SegTree(int _n) : n(_n) {
		for (base = 1; base < n; base <<= 1);
		T.resize(base + base);
		L.resize(base + base);
		for (int i = base; i < base + base; i++) L[i] = i - base + 1;
		for (int i = base - 1; i >= 1; i--) L[i] = L[i << 1];
	}

	void chk_node(int idxl, int idxr, int y, int r) {
		auto itl = T[idxl].s.lower_bound({y, 0});
		auto itr = T[idxr].s.lower_bound({y, 0});
		auto tmpl = itl, tmpr = itr;
		if (idxl == idxr) {
			for (int i = 0; i < 3; i++) {
				if (itl == T[idxl].s.end()) break;
				chk(itl->second);
				// if (itl->first >= (long long)y + r + r) break;
				if (i < K - 1) itl++;
			}
		} else {
			for (int i = 0; i < 3; i++) {
				bool fl = (itl == T[idxl].s.end());
				bool fr = (itr == T[idxr].s.end());
				if (fl && fr) break;
				if (fr || (!fl && itl->first < itr->first)) {
					chk(itl->second);
					if (i < 2) itl++;
				} else {
					chk(itr->second);
					if (i < 2) itr++;
				}
			}
		}
		itl = tmpl; itr = tmpr;
		if (idxl == idxr) {
			for (int i = 0; i < 3; i++) {
				if (itl == T[idxl].s.begin()) break;
				itl--;
				chk(itl->second);
				// if (itl->first <= (long long)y - r - r) break;
			}
		} else {
			for (int i = 0; i < 3; i++) {
				bool fl = (itl == T[idxl].s.begin());
				bool fr = (itr == T[idxr].s.begin());
				if (fl && fr) break;
				if (fr || (!fl && prev(itl)->first < prev(itr)->first)) {
					itl--;
					chk(itl->second);
				} else {
					itr--;
					chk(itr->second);
				}
			}
		}

		// auto it = T[idx].s.lower_bound({y, 0});
		// auto tmp = it;
		// for (int i = 0; i < K; i++) {
		// 	if (it == T[idx].s.end()) break;
		// 	chk(it->second);
		// 	if (it->first >= (long long)y + r + r) break;
		// 	if (i < K - 1) it++;
		// }
		// it = tmp;
		// for (int i = 0; i < K; i++) {
		// 	if (it == T[idx].s.begin()) break;
		// 	it--;
		// 	chk(it->second);
		// 	if (it->first <= (long long)y - r - r) break;
		// }
	}

	void upd(int p, int q, pii x) {
		p += base; q += base;
		p--; q--;
		while (p <= q) {
			if (p & 1) T[p++].s.insert(x);
			if (~q & 1) T[q--].s.insert(x);
			p >>= 1; q >>= 1;
		}
	}

	void get(int p, int q, int y, int r) {
		p += base; q += base;
		p--; q--;
		while (p > 1) {
			chk_node(p, q, y, r);
			p >>= 1; q >>= 1;
		}
	}

	// void get(int p, int y, int r, int li) {
	// 	p += base; p--;
	// 	while (p >= 1) {
	// 		if (L[p] <= li) break;
	// 		chk_node(p, y, r);
	// 		p >>= 1;
	// 	}
	// }
};

int main() {
	rf(N);
	vector<int> v;
	for (int i = 1; i <= N; i++) {
		rf(X[i]); rf(Y[i]); rf(R[i]);
		XL[i] = X[i] - R[i], XR[i] = X[i] + R[i];
		v.push_back(XL[i]);
		v.push_back(XR[i]);
	}
	sort(v.begin(), v.end());
	v.erase(unique(v.begin(), v.end()), v.end());
	for (int i = 1; i <= N; i++) {
		XL[i] = lower_bound(v.begin(), v.end(), XL[i]) - v.begin() + 1;
		XR[i] = lower_bound(v.begin(), v.end(), XR[i]) - v.begin() + 1;
	}

	int M = v.size();
	SegTree seg(M);

	vector<int> idx(N);
	iota(idx.begin(), idx.end(), 1);
	sort(idx.begin(), idx.end(), [&](int a, int b) {
		return pii(R[a], -a) > pii(R[b], -b);
	});

	for (int i : idx) {
		cur = i;
		ans[i] = i;
		seg.get(XL[i], XR[i], Y[i], R[i]);
		// seg.get(XL[i], Y[i], R[i], 0);
		// seg.get(XR[i], Y[i], R[i], XL[i]);
		if (ans[i] == i) seg.upd(XL[i], XR[i], {Y[i], i});
	}

	for (int i = 1; i <= N; i++) printf("%d ", ans[i]); puts("");
	return 0;
}

Compilation message (stderr)

circle_selection.cpp: In function 'int main()':
circle_selection.cpp:183:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  183 |  for (int i = 1; i <= N; i++) printf("%d ", ans[i]); puts("");
      |  ^~~
circle_selection.cpp:183:54: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  183 |  for (int i = 1; i <= N; i++) printf("%d ", ans[i]); puts("");
      |                                                      ^~~~

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