QOJ.ac

QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#300055#7310. Circular SectorsmshcherbaRE 3ms4236kbC++207.8kb2024-01-07 17:01:282024-01-07 17:01:29

Judging History

你现在查看的是最新测评结果

  • [2024-01-07 17:01:29]
  • 评测
  • 测评结果:RE
  • 用时:3ms
  • 内存:4236kb
  • [2024-01-07 17:01:28]
  • 提交

answer

#include <bits/stdc++.h>

using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)
#define SZ(a) int(a.size())
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;

const db EPS = 1e-9;
const db PI = acos(-1.0);

struct Pt
{
	db x, y;
	Pt operator+(const Pt& p) const
	{
		return {x + p.x, y + p.y};
	}
	Pt operator-(const Pt& p) const
	{
		return {x - p.x, y - p.y};
	}
	Pt operator*(db d) const
	{
		return {x * d, y * d};
	}
	Pt operator/(db d) const
	{
		return {x / d, y / d};
	}
};

db sq(const Pt& p)
{
	return p.x * p.x + p.y * p.y;
}

db abs(const Pt& p)
{
	return sqrt(sq(p));
}

int sgn(db x)
{
	return (EPS < x) - (x < -EPS);
}

Pt perp(const Pt& p)
{
	return {-p.y, p.x};
}

db dot(const Pt& p, const Pt& q)
{
	return p.x * q.x + p.y * q.y;
}

db cross(const Pt& p, const Pt& q)
{
	return p.x * q.y - p.y * q.x;
}

db orient(const Pt& p, const Pt& q, const Pt& r)
{
	return cross(q - p, r - p) / abs(q - p);
}

ostream& operator<<(ostream& os, const Pt& p)
{
	return os << "(" << p.x << "," << p.y << ")";
}

struct Line
{
	Pt n;
	db c;
	Line(const Pt& p, const Pt& q):
		n(perp(q - p)), c(-dot(n, p)) {}
	db side(const Pt& p) const
	{
		return dot(n, p) + c;
	}
	db sqDist(const Pt& p) const
	{
		return side(p) * side(p) / (db)sq(n);
	}
	Pt proj(const Pt& p) const
	{
		return p - n * side(p) / sq(n);
	}
};

bool parallel(const Line& l1, const Line& l2)
{
	return sgn(cross(l1.n, l2.n)) == 0;
}

Pt inter(const Line& l1, const Line& l2)
{
	db d = cross(l1.n, l2.n);
	assert(sgn(d) != 0);
	return perp(l2.n * l1.c - l1.n * l2.c) / d;
}

bool inDisk(const Pt& a, const Pt& b,
	const Pt& p)
{
	return sgn(dot(a - p, b - p)) <= 0;
}

bool onSegment(const Pt& a, const Pt& b,
	const Pt& p)
{
	return sgn(orient(a, b, p)) == 0
		&& inDisk(a, b, p);
}

vector<Pt> circleLine(const Pt& o, db r,
	const Line& l)
{
	db h2 = r * r - l.sqDist(o);
	if (sgn(h2) == -1)
		return {};
	Pt p = l.proj(o);
	if (sgn(h2) == 0)
		return {p};
	Pt h = perp(l.n) * sqrt(h2) / abs(l.n);
	return {p - h, p + h};
}

vector<Pt> circleCircle(const Pt& o1, db r1,
	const Pt& o2, db r2)
{
	Pt d = o2 - o1;
	db d2 = sq(d);
	if (sgn(d2) == 0)
	{
		return {};
	}
	db pd = (d2 + r1 * r1 - r2 * r2) / 2;
	db h2 = r1 * r1 - pd * pd / d2;
	if (sgn(h2) == -1)
		return {};
	Pt p = o1 + d * pd / d2;
	if (sgn(h2) == 0)
		return {p};
	Pt h = perp(d) * sqrt(h2 / d2);
	return {p - h, p + h};
}

bool strictlyIncreasing(db a, db b, db c)
{
	return sgn(a - b) < 0 && sgn(b - c) < 0;
}

struct Sector
{
	Pt o;
	db r, s, theta;
	Pt p1, p2;
};

vector<Sector> sectors;
vector<Line> lines;

struct Event
{
	db x;
	int i, j, k;
	bool operator<(const Event& event) const
	{
		return sgn(x - event.x) < 0;
	}
};

db getY(const PII& ij, db x)
{
	const auto& [i, j] = ij;
	if (j == 0)
	{
		const Line& l = lines[i];
		return -(l.n.x * x + l.c) / l.n.y;
	}
	const Pt& o = sectors[i].o;
	db r = sectors[i].r;
	return o.y + j * sqrt(max(0.0, r * r - (x - o.x) * (x - o.x)));
};

struct Comparator
{
	static db x;
	bool operator() (const PII& a, const PII& b) const
	{
		return sgn(getY(a, x) - getY(b, x)) < 0;
	}
};

db Comparator::x;

db getAreaOfCirclePart(db r, db x)
{
	db co = clamp(x / r, -1.0, 1.0);
	db alpha = acos(co);
	return (PI - alpha + co * sqrt(1 - co * co)) * r * r / 2;	
}

void solve(int n)
{
	sectors.resize(n);
	lines.clear();
	VI linesBalances;
	for (auto& [o, r, s, theta, p1, p2] : sectors)
	{
		cin >> o.x >> o.y >> r >> s >> theta;
		p1 = {o.x + r * cos(s), o.y + r * sin(s)};
		linesBalances.PB(sgn(cos(s)));
		p2 = {o.x + r * cos(s + theta), o.y + r * sin(s + theta)};
		linesBalances.PB(-sgn(cos(s + theta)));
		lines.PB({o, p1});
		lines.PB({o, p2});
	}
	vector<Event> events;
	FOR(i, 0, n)
	{
		const auto& [o, r, s, theta, p1, p2] = sectors[i];
		if (strictlyIncreasing(s, PI, s + theta)
			|| strictlyIncreasing(s, 3 * PI, s + theta))
		{
			events.PB({o.x - r, i, -1, 1});
			events.PB({o.x - r, i, 1, 1});
		}
		if (strictlyIncreasing(s, 2 * PI, s + theta))
		{
			events.PB({o.x + r, i, -1, -1});
			events.PB({o.x + r, i, 1, -1});
		}
		if (sgn(p1.y - o.y) > 0
			|| (sgn(p1.y - o.y) == 0 && sgn(p1.x - o.x) > 0))
		{
			events.PB({p1.x, i, 1, -1});
		}
		else
		{
			events.PB({p1.x, i, -1, 1});
		}
		if (sgn(p2.y - o.y) > 0
			|| (sgn(p2.y - o.y) == 0 && sgn(p2.x - o.x) < 0))
		{
			events.PB({p2.x, i, 1, 1});
		}
		else
		{
			events.PB({p2.x, i, -1, -1});
		}
		int idxLine = 2 * i;
		for (const Pt& p : {p1, p2})
		{
			assert(sgn(p.x - o.x) != 0);
			bool toLeft = sgn(o.x - p.x) < 0;
			events.PB({o.x, idxLine, 0, toLeft ? 1 : -1});
			events.PB({p.x, idxLine, 0, toLeft ? -1 : 1});
			idxLine++;
		}
		FOR(j, 0, n)
		{
			if (j == i)
				continue;
			const auto& sector = sectors[j];
			if (j < i)
			{
				vector<Pt> cc = circleCircle(o, r, sector.o, sector.r);
				for (const Pt& q : cc)
				{
					// redundant events
					for (int idx : {i, j})
						for (int lu : {-1, 1})
							events.PB({q.x, idx, lu, 0});
				}
			}
			idxLine = 2 * j;
			for (const Pt& p : {sector.p1, sector.p2})
			{
				vector<Pt> cl = circleLine(o, r, lines[idxLine]);
				for (const Pt& q : cl)
				{
					if (onSegment(sector.o, p, q))
					{
						for (int lu : {-1, 1})
							events.PB({q.x, i, lu, 0});
						events.PB({q.x, idxLine, 0, 0});
					}
				}
				idxLine++;
			}
		}
	}
	FOR(i, 0, 2 * n)
	{
		Pt o1 = sectors[i / 2].o;
		Pt pi = i % 2 == 0 ? sectors[i / 2].p1 : sectors[i / 2].p2;
		FOR(j, 0, i)
		{
			if (i / 2 == j / 2 || parallel(lines[i], lines[j]))
				continue;
			Pt o2 = sectors[j / 2].o;
			Pt pj = j % 2 == 0 ? sectors[j / 2].p1 : sectors[j / 2].p2;
			Pt q = inter(lines[i], lines[j]);
			if (onSegment(o1, pi, q)
				&& onSegment(o2, pj, q))
			{
				events.PB({q.x, i, 0, 0});
				events.PB({q.x, j, 0, 0});
			}
		}
	}
	set<PII, Comparator> curves;
	sort(ALL(events));
	db ans = 0;
	for(int idxEvent = 0; ;)
	{
		set<PII> del, add, delAdd;
		int ptr = idxEvent;
		while (ptr < SZ(events) && !(events[idxEvent] < events[ptr]))
		{
			//cerr << "event " << events[ptr].x << " " << events[ptr].i << " " << events[ptr].j << " " << events[ptr].k << endl;
			PII cur = {events[ptr].i, events[ptr].j};
			if (events[ptr].k == -1)
				del.insert(cur);
			else if (events[ptr].k == 1)
				add.insert(cur);
			else
				delAdd.insert(cur);
			ptr++;
		}
		for (const PII& ij : del)
		{
			curves.erase(ij);
		}
		for (const PII& ij : delAdd)
		{
			if (del.count(ij) || add.count(ij) || !curves.count(ij))
				continue;
			curves.erase(ij);
			add.insert(ij);
		}
		if (ptr == SZ(events))
			break;
		db xl = events[idxEvent].x, xr = events[ptr].x;
		Comparator::x = (xl + xr) / 2;
		for (const PII& ij : add)
		{
			curves.insert(ij);
		}
		int bal = 0;
		for (const PII& ij : curves)
		{
			const auto& [i, j] = ij;
			int deltaBal = j == 0 ? linesBalances[i] : -j;
			assert(bal >= 0);
			if (bal == 0 || bal + deltaBal == 0)
			{
				db area;
				if (j == 0)
				{
					area = (getY(ij, xl) + getY(ij, xr)) * (xr - xl) / 2;
				}
				else
				{
					const Pt& o = sectors[i].o;
					db r = sectors[i].r;
					area = j * (getAreaOfCirclePart(r, xr - o.x) - getAreaOfCirclePart(r, xl - o.x)) + o.y * (xr - xl);
				}
				ans -= deltaBal * area;
			}
			bal += deltaBal;
		}
		assert(bal == 0);
		idxEvent = ptr;
	}
	cout << ans << "\n";
}

int main()
{
	ios::sync_with_stdio(0); 
	cin.tie(0);
	cout << fixed << setprecision(15);
	int n;
	while (cin >> n)
	{
		solve(n);
	}
	return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 1ms
memory: 4224kb

input:

2
-3 -5 5 0.705 0.217
-5 1 4 3.070 4.136
1
-4 -4 1 0.485 2.260
3
4 4 4 4.266 4.673
2 -4 5 0.353 5.565
-2 1 3 3.974 0.207

output:

35.800499999999985
1.129999999999999
106.444931438703563

result:

ok 3 numbers

Test #2:

score: 0
Accepted
time: 0ms
memory: 4152kb

input:

2
-2 -1 5 2.250 0.555
-3 0 2 2.189 0.788
2
-5 1 5 0.432 1.643
3 5 5 4.779 2.014
2
2 0 3 4.194 2.691
4 -3 4 0.998 5.376
2
-3 1 4 5.841 2.968
-4 -3 2 4.151 4.029
2
4 -1 5 2.416 2.385
5 0 3 5.315 2.683
2
-2 0 2 3.972 1.255
2 -5 2 0.912 5.211
2
1 0 4 2.826 3.794
-2 -3 1 3.335 3.836
2
-5 4 2 2.496 2.273
...

output:

6.937500000000004
45.712499999999999
43.533920893527551
31.802000000000007
41.886000000000010
12.932000000000000
31.713102368390359
9.889999999999997
3.811499999999999
26.789999999999999
37.187500000000007
10.700500000000000
31.423499999999983
47.664000000000001
25.456499999999998
54.013595092918770...

result:

ok 250 numbers

Test #3:

score: 0
Accepted
time: 3ms
memory: 4236kb

input:

3
1 -1 5 3.089 5.717
-2 0 2 4.806 3.257
0 -3 2 5.069 3.049
3
-2 -4 2 4.616 2.875
2 -2 4 5.798 3.097
-1 2 1 0.064 5.418
3
-1 1 2 4.105 3.883
0 5 4 1.936 4.292
2 -5 2 0.278 4.486
3
3 -5 5 3.208 4.696
-2 -4 3 3.609 0.906
-2 4 3 3.796 4.334
3
0 -1 1 4.313 0.711
2 -2 1 2.962 0.344
-4 2 5 2.524 3.043
3
-1...

output:

74.157879726552892
33.234999999999999
47.749461461744588
82.280000000000015
38.564999999999998
57.287499999999994
16.887499999999999
30.812466324073270
18.266137364384576
43.264634755237466
42.494217510621972
26.132749175803266
26.404499999999981
30.106728114671803
48.936999999999998
23.139499999999...

result:

ok 166 numbers

Test #4:

score: -100
Runtime Error

input:

4
4 3 4 1.727 2.114
-5 3 2 5.010 2.690
-1 1 5 4.078 2.852
1 5 5 2.974 4.884
4
3 4 1 5.626 2.021
2 -4 1 1.241 0.231
4 -4 5 0.323 5.472
-2 5 2 2.648 1.031
4
-1 -1 2 0.156 3.062
2 2 1 1.127 4.124
5 3 5 1.105 5.179
4 2 3 3.363 4.235
4
-2 -3 3 1.013 4.047
0 -5 5 1.829 4.952
-4 0 5 2.029 4.410
3 -1 4 1.40...

output:


result: