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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 |
---|---|---|---|---|---|---|---|---|---|
#736106 | #9520. Concave Hull | PHarr | TL | 734ms | 4096kb | C++20 | 3.0kb | 2024-11-12 00:45:01 | 2024-11-12 00:45:01 |
Judging History
answer
#include <bits/stdc++.h>
using i32 = int32_t;
using i64 = long long;
#define int i64
const int inf = LLONG_MAX / 2;
struct Point {
i64 x, y;
Point(i64 x = 0, i64 y = 0) : x(x), y(y) {};
};
using Vec = Point;
using Points = std::vector<Point>;
Vec operator-(Vec u, Vec v) { return Vec(u.x - v.x, u.y - v.y); }
int operator^(Vec u, Vec v) { return u.x * v.y - u.y * v.x; }
bool operator<(Point A, Point B) {
if (A.x != B.x) return A.x < B.x;
return A.y < B.y;
}
bool check(Point p, Point q, Point r) {
return 0 < ((q - p) ^ (r - q));
}
std::pair<Points, Points> chull(Points &ps) {
std::sort(ps.begin(), ps.end());
std::vector<int> I{0}, used(ps.size());
for (int i = 1; i < ps.size(); i++) { // 下凸包
while (I.size() > 1 and !check(ps[I[I.size() - 2]], ps[I.back()], ps[i]))
used[I.back()] = 0, I.pop_back();
used[i] = 1, I.push_back(i);
}
for (int i = ps.size() - 2, tmp = I.size(); i >= 0; i--) { // 上凸包
if (used[i]) continue;
while (I.size() > tmp and !check(ps[I[I.size() - 2]], ps[I.back()], ps[i]))
used[I.back()] = 0, I.pop_back();
used[i] = 1, I.push_back(i);
}
Points H;
I.pop_back();
for (auto i: I)
H.push_back(ps[i]);
Points notH;
for (int i = 1; i < ps.size(); i++) {
if (used[i]) continue;
notH.push_back(ps[i]);
}
return std::pair(H, notH);
}
int area(Point a, Point b, Point c) {
return std::abs((b - a) ^ (c - a));
}
void solve() {
int n;
std::cin >> n;
Points ps(n);
for (auto &[x, y]: ps)
std::cin >> x >> y;
auto [c1, new_ps] = chull(ps);
ps = move(new_ps);
int chull_area = 0;
for (int i = 0; i < c1.size(); i++)
chull_area += c1[i] ^ c1[(i + 1) % c1.size()];
if (ps.empty()) {
std::cout << -1 << "\n";
} else if (ps.size() < 1e9) {
int ret = inf;
for (int i = 0; i < ps.size(); i++)
for (int j = 0; j < c1.size(); j++)
ret = std::min(ret, area(ps[i], c1[j], c1[(j + 1) % c1.size()]));
std::cout << chull_area - ret << "\n";
} else {
auto [c2, _] = chull(ps);
int it = 0, val = area(c2[0], c1[0], c1[1]);
for (int i = 1, x; i < c1.size(); i++) {
x = area(c2[0], c1[i], c1[(i + 1) % c1.size()]);
if (x < val) val = x, it = i;
}
int ret = val;
for (int i = 1; i < c2.size(); i++) {
val = area(c2[i], c1[it], c1[(it + 1) % c1.size()]);
for (int x; true; it = (it + 1) % c1.size()) {
x = area(c2[i], c1[(it + 1) % c1.size()], c1[(it + 2) % c1.size()]);
if (x >= val) break;
val = x;
}
ret = std::min(ret, val);
}
std::cout << chull_area - ret << "\n";
}
return;
}
i32 main() {
i32 T;
std::cin >> T;
while (T--)
solve();
return 0;
}
詳細信息
Test #1:
score: 100
Accepted
time: 0ms
memory: 3616kb
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: 0ms
memory: 3584kb
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: 75ms
memory: 3740kb
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: 85ms
memory: 3596kb
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: 734ms
memory: 4096kb
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: 621ms
memory: 3856kb
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: -100
Time Limit Exceeded
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...