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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#497360#7734. Intersection over UnionlonelywolfTL 1ms3856kbC++174.1kb2024-07-29 02:51:082024-07-29 02:51:09

Judging History

你现在查看的是最新测评结果

  • [2024-07-29 02:51:09]
  • 评测
  • 测评结果:TL
  • 用时:1ms
  • 内存:3856kb
  • [2024-07-29 02:51:08]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef double LD;
typedef pair <int, int> pii;


#define cp const point &
const LD eps = 0;
int sgn (LD x) { return x > eps ? 1 : (x < -eps ? -1 : 0); }
LD sqr (LD x) { return x * x; }
struct point {
	LD x, y;
	point () {}
	point (LD xx, LD yy) { x = xx, y = yy; }
	point operator + (cp a) const { return {x + a.x, y + a.y}; }
	point operator - (cp a) const { return {x - a.x, y - a.y}; }
	point operator * (LD a) const { return {x * a, y * a}; }
	point operator / (LD a) const { return {x / a, y / a}; }
	point rot90() const { return {-y, x}; }
	bool operator == (cp a) const {
		return x == a.x && y == a.y;	
	}
	void read() {
		int xx, yy;
		cin >> xx >> yy;
		x = xx, y = yy;
	}
};

LD det (cp a, cp b) { return a.x * b.y - b.x * a.y; }
LD dot (cp a, cp b) { return a.x * b.x + a.y * b.y; }
LD dis (cp a, cp b) { return sqrt (sqr (a.x - b.x) + sqr(a.y - b.y)); }

bool turn_left(cp a, cp b, cp c) {
	return sgn (det (b - a, c - a)) > 0;
}

#define cl const line &
struct line {
	point s, t;
	line () {}
	line (point ss, point tt) { s = ss, t = tt; }
	bool operator == (cl a) const {
		return s == a.s && t == a.t;
	}
};

point line_inter (cl a, cl b) {
	LD s1 = det (a.t - a.s, b.s - a.s);
	LD s2 = det (a.t - a.s, b.t - a.s);
	return (b.s * s2 - b.t * s1) / (s2 - s1);
}
bool turn_left (cl l, cp p) { return turn_left(l.s, l.t, p); }

line h[8];
LD hpi_nosort() {
	line q[8]; int l = 0, r = -1;
	point ret[8];
	q[0] = h[0]; q[1] = h[1]; r = 1;
	ret[1] = line_inter(q[0], q[1]);
	for (int t = 2; t < 8; t++) {
		auto &i = h[t];
		while (l < r && !turn_left(i, ret[r]))
			-- r;
		while (l < r && !turn_left(i, ret[l + 1]))
			++ l;
		++ r; q[r] = i;
		if (l != r) ret[r] = line_inter(q[r - 1], q[r]);
	}
	ret[l] = line_inter(q[r], q[l]);
	LD area = 0;
	for (int i = l; i <= r; i++) area += det(ret[i], ret[i == r ? l : i + 1]);
	return area;
}


LD ans, sq;
LD check (LD x, LD y) {
	h[1] = {{-1, -y}, {1, -y}};
	h[3] = {{x, -1}, {x, 1}};
	h[5] = {{1, y}, {-1, y}};
	h[7] = {{0, 1}, {0, -1}};
	LD a = hpi_nosort();
	LD f = x * y * 4; 
	return a / (f + sq - a);
}

const LD Rp = (sqrt(5) - 1) / 2, Lp = 1 - Rp;
LD check (LD x) {
	LD l = 0, r = 1, lv = -1, rv = -1, v = 0;
	for (int t = 42; t; t--) {
		LD b = (r - l) * Rp;
		LD lmid = r - b, rmid = l + b;
		if (lv == -1) lv = check(x, lmid);
		if (rv == -1) rv = check(x, rmid);
		if (rv < lv) rv = lv, lv = -1, r = rmid;
		else lv = rv, rv = -1, l = lmid;
	}
	ans = max(ans, v = max(lv, rv));
	return v;
}


void work() {
	vector <point> p;
	for (int i = 0; i < 4; i++) {
		point u; u.read();
		p.push_back(u);
	}
	if (!turn_left(p[0], p[1], p[2])) {
		reverse(p.begin(), p.end());
	}
	if (sgn(det(p[1] - p[0], {1, 0})) == 0 || sgn(det(p[2] - p[1], {1, 0})) == 0) {
		cout << "1\n";
		return;
	}
	auto center = (p[0] + p[2]) / 2;
	{
		int k = 0;
		for (int i = 0; i < 4; i++) {
			if (p[i].x < p[k].x) k = i;
		}
		vector <point> q;
		for (int i = 0; i < 4; i++) q.push_back(p[(i + k) % 4] - center);
		p = move(q);
	}
	sq = abs(det(p[1] - p[0], p[2] - p[1]));
	LD Lx = p[2].x;
	LD Ly = p[3].y;
	for (auto &[x, y] : p) {
		x /= Lx;
		y /= Ly;
	}
	sq /= Lx * Ly;

	/*{
		base[0],
		{{-1, -y}, {1, -y}},
		base[1],
		{{x, -1}, {x, 1}},
		base[2],
		{{1, y}, {-1, y}},
		base[3],
		{{0, 1}, {0, -1}}
	}*/
	h[0] = {p[0], p[1]};
	h[2] = {p[1], p[2]};
	h[4] = {p[2], p[3]};
	h[6] = {p[3], p[0]};
	LD xl = 0, xr = 1, lv = -1, rv = -1;
	ans = check(1 - 1e-9);
	for (int t = 38; t; t--) {
		LD b = (xr - xl) * Rp;
		LD lmid = xr - b, rmid = xl + b;
		if (lv == -1) lv = check(lmid);
		if (rv == -1) rv = check(rmid);
		//LD lv = check(lmid), rv = check(rmid);
		if (rv < lv) rv = lv, lv = -1, xr = rmid;
		else lv = rv, rv = -1, xl = lmid;
	}
	check((xl + xr) / 2);
	cout << (double)ans << '\n'; 
}

int main() {
	ios::sync_with_stdio(false); cin.tie(0);
	int T = 1;
	cin >> T;
	cout << fixed << setprecision(10);
	for (int ca = 1; ca <= T; ca ++) {
		work();
	}
}

Details

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Test #1:

score: 100
Accepted
time: 1ms
memory: 3856kb

input:

3
0 2 2 0 0 -2 -2 0
7 -2 9 -2 9 2 7 2
7 13 11 10 5 2 1 5

output:

0.7071067812
1
0.6238432248

result:

ok 3 numbers

Test #2:

score: -100
Time Limit Exceeded

input:

10000
-568767734 379152673 -565681345 -54946093 -131582579 -51859704 -134668968 382239062
-194884120 -559906233 -194884142 -158042604 -998611400 -158042648 -998611378 -559906277
459335966 -945199065 478030260 -934243779 450535683 -887326546 431841389 -898281832
-483567491 491964356 -523827401 408140...

output:

0.9929654125
0.9999999315
0.5908698157
0.6217704849
0.5788323841
1
0.4999999974
0.6852345806
0.4559617198
0.5002873939
0.9802961106
0.4920435718
0.5440373887
0.3804801071
0.9231183318
0.8925587009
0.6176803196
0.9456769702
0.4998743720
0.9999543878
0.6474214765
0.7778122048
0.5000000000
0.9560555504...

result: