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QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#768308 | #9520. Concave Hull | DopplerXD | TL | 783ms | 11568kb | C++20 | 3.6kb | 2024-11-21 08:59:10 | 2024-11-21 08:59:11 |
Judging History
answer
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N = 1e5 + 5;
const double pi = acos(-1.0);
const double eps = 1e-8;
// 判断 x 的大小,<0 返回 -1,>0 返回 1,==0 返回 0
int sgn(ll x) {
if (abs(x) == 0) return 0;
else return x < 0 ? -1 : 1;
}
struct Point {
ll x, y;
Point() {}
Point(ll x, ll y) : x(x), y(y) {}
Point operator + (const Point& B) const { return Point(x + B.x, y + B.y); }
Point operator - (const Point& B) const { return Point(x - B.x, y - B.y); }
// Point operator * (double k) const { return Point(x * k, y * k); }
// Point operator / (double k) const { return Point(x / k, y / k); }
bool operator == (const Point& B) const {
return sgn(x - B.x) == 0 && sgn(y - B.y) == 0;
}
bool operator < (const Point& B) const {
return sgn(x - B.x) < 0 || sgn(x - B.x) == 0 && sgn(y - B.y) < 0;
}
};
typedef Point Vector;
class Geometry {
public:
static double Distance(const Point& A, const Point& B) {
return sqrt((A.x - B.x) * (A.x - B.x) + (A.y - B.y) * (A.y - B.y));
}
static ll Cross(const Vector& A, const Vector& B) {
return A.x * B.y - A.y * B.x;
}
static ll Area2(const Point& A, const Point& B, const Point& C) {
return Cross(B - A, C - A);
}
};
class PolygonOps {
public:
static ll Area(int n, Point* ch) {
ll area = 0;
for (int i = 0; i < n; i++)
area += Geometry::Cross(ch[i], ch[(i + 1) % n]);
return area;
}
};
int Convex_hull(Point* p, int n, Point* ch) {
sort(p, p + n);
int v = 0;
for (int i = 0; i < n; i++) {
while (v > 1 && sgn(Geometry::Cross(ch[v - 1] - ch[v - 2], p[i] - ch[v - 1])) <= 0) {
v--;
}
ch[v++] = p[i];
}
int j = v;
for (int i = n - 1; i >= 0; i--) {
while (v > j && sgn(Geometry::Cross(ch[v - 1] - ch[v - 2], p[i] - ch[v - 1])) <= 0) {
v--;
}
ch[v++] = p[i];
}
if (n > 1) v--;
return v;
}
int n, n_left;
Point p[N], Left[N];
Point ch[N], chL[N];
void solve() {
cin >> n;
n_left = 0;
for (int i = 0; i < n; i++) {
cin >> p[i].x >> p[i].y;
}
int v = Convex_hull(p, n, ch);
set<Point> st;
for (int i = 0; i < v; i++) {
st.emplace(ch[i]);
}
for (int i = 0; i < n; i++) {
if (!st.count(p[i])) {
Left[n_left++] = p[i];
}
}
int vL = Convex_hull(Left, n_left, chL);
if (vL == 0) {
cout << -1 << '\n';
return;
}
// cerr << "v: " << v << '\n';
// cerr << "vL: " << vL << ", n_left: " << n_left << '\n';
ll area = PolygonOps::Area(v, ch);
ll ans = 0;
ch[v] = ch[0];
chL[vL] = chL[0];
// for (int i = 0, j = 0; i < v; i++) {
// ll tri_0, tri_1;
// int cnt = 0;
// while (cnt < v &&
// (tri_0 = Geometry::Area2(chL[j], ch[i], ch[i + 1])) >=
// (tri_1 = Geometry::Area2(chL[j + 1], ch[i], ch[i + 1]))) {
// j = (j + 1) % vL;
// cnt++;
// }
// ans = std::max(ans, area - tri_0);
// }
for (int i = 0; i < v; i++) {
for (int j = 0; j < vL; j++) {
ll tri = Geometry::Area2(chL[j], ch[i], ch[i + 1]);
ans = std::max(ans, area - tri);
}
}
cout << ans << '\n';
}
int main() {
ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
int _T = 1;
cin >> _T;
while (_T--)
solve();
return 0;
}
詳細信息
Test #1:
score: 100
Accepted
time: 0ms
memory: 7688kb
input:
2 6 -2 0 1 -2 5 2 0 4 1 2 3 1 4 0 0 1 0 0 1 1 1
output:
40 -1
result:
ok 2 lines
Test #2:
score: 0
Accepted
time: 1ms
memory: 7636kb
input:
10 243 -494423502 -591557038 -493438474 -648991734 -493289308 -656152126 -491185085 -661710614 -489063449 -666925265 -464265894 -709944049 -447472922 -737242534 -415977509 -773788538 -394263365 -797285016 -382728841 -807396819 -373481975 -814685302 -368242265 -818267002 -344482838 -833805545 -279398...
output:
2178418010787347715 1826413114144932145 1651687576234220014 1883871859778998985 2119126281997959892 894016174881844630 2271191316922158910 1998643358049669416 1740474221286618711 1168195646932543192
result:
ok 10 lines
Test #3:
score: 0
Accepted
time: 24ms
memory: 7600kb
input:
1000 125 64661186 -13143076 302828013 -185438065 -418713797 -191594241 430218126 -397441626 354327250 -836704374 149668812 -598584998 311305970 66790541 199720625 -592356787 468137 -584752683 258775829 96211747 -358669612 -134890109 -129221188 -998432368 -277309896 -140056561 356901185 420557649 -51...
output:
1986320445246155278 1900093336073022078 1612088392301142476 2012259136539173407 1819942017252118749 1772230185841892196 1164835025329039520 1527446155241140517 1807368432185303666 1236918659444944569 1306839249967484778 1984123720246784099 1868728080720036006 667458140583450322 2127932992585026491 4...
result:
ok 1000 lines
Test #4:
score: 0
Accepted
time: 34ms
memory: 7624kb
input:
10000 9 484630042 51929469 -40468396 -517784096 98214104 -103353239 629244333 -475172587 106398764 153884485 49211709 -44865749 1 10 166321833 -247717657 406208245 668933360 13 548702216 -631976459 37150086 -292461024 707804811 -486185860 239775286 -903166050 10096571 -541890068 686103484 558731937 ...
output:
950319193795831919 1661025342421008544 1285164852091455548 1159924751776806668 1206071151805176722 794021230296144371 699991678992587791 1133990718508584290 1486311831172661605 984875884297072200 1327767982175057345 758247019006396699 1355381234262206155 1139262078529131471 1613462877860621700 12392...
result:
ok 10000 lines
Test #5:
score: 0
Accepted
time: 263ms
memory: 8236kb
input:
100 439 471536154 -312612104 155692036 -937312180 -461624056 -357636609 236656684 -911414873 -288656914 -74788431 -465779694 -381475149 -334197401 -903065737 491513067 -447615916 337664889 -852236281 -281689379 -53519178 -159101704 -920779200 -326159514 -95396204 21868593 -994282736 488425383 -41046...
output:
1973162724053130487 2054612790507830954 1726805687754843724 1699420177872986528 2129388571309147631 2198295137903288810 1697185883164440272 1219697450095721478 2027023581922285255 1674691247127206655 1673105966817209954 2179188692918747442 2146544318743443141 2230356305133660648 1676850321902993764 ...
result:
ok 100 lines
Test #6:
score: 0
Accepted
time: 167ms
memory: 8120kb
input:
100 1362 -467257672 -466669 -467054869 -478108 -466973270 -481776 -466556983 -499770 -466329414 -508693 -466248017 -511805 -466158865 -513786 -466101273 -515035 -465927700 -518748 -465717624 -522106 -465303448 -528127 -465124548 -530726 -464649746 -536693 -464554872 -537799 -464478196 -538680 -46416...
output:
1666097696993497 1791366071767866 1806187278469532 1683419854733713 1685891971828916 1730190225081651 1787048201197565 1850308098208660 1710694884375502 1826363113637639 1816375352374659 2047431269497691 1549806516003854 1829438662895747 1678707854135065 1687423392883819 2121960009997761 16687219538...
result:
ok 100 lines
Test #7:
score: 0
Accepted
time: 783ms
memory: 10200kb
input:
2 62666 -486101704 -505730259 -486101698 -506082699 -486101689 -506111362 -486101682 -506126031 -486101528 -506293759 -486101259 -506556385 -486101196 -506613483 -486101154 -506648604 -486100935 -506831392 -486100631 -507083675 -486100470 -507199151 -486100233 -507368923 -486100193 -507397039 -48609...
output:
2178736946152219010 1825181940245096152
result:
ok 2 lines
Test #8:
score: 0
Accepted
time: 641ms
memory: 11568kb
input:
2 100000 301945097 76373292 467957663 -286424714 8245445 -597212507 -474204621 -708828667 184159460 105942538 443435905 -429212625 490658771 -382198656 82512047 -612522436 -228221388 -965890088 394789011 -145801151 -106120174 -528202395 428939626 -194437311 497429477 -527407728 365739746 -114818962 ...
output:
2502889432701099511 2267250485735988121
result:
ok 2 lines
Test #9:
score: -100
Time Limit Exceeded
input:
2 100000 221128057 -975244780 -618765360 -785575858 422567455 -906331476 -988680318 -150037424 -929870145 367887908 -757813541 -652471177 291995621 -956419655 -785381507 619012026 468864522 -883270094 -588416522 808557973 859345881 511394814 988105866 153775152 216931298 -976186873 467050734 8842305...