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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 HullPHarrTL 734ms4096kbC++203.0kb2024-11-12 00:45:012024-11-12 00:45:01

Judging History

你现在查看的是最新测评结果

  • [2024-11-12 00:45:01]
  • 评测
  • 测评结果:TL
  • 用时:734ms
  • 内存:4096kb
  • [2024-11-12 00:45:01]
  • 提交

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...

output:


result: