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Submission #701626

# Submission time Handle Problem Language Result Execution time Memory
701626 2023-02-21T15:40:22 Z Cyanmond Roads (CEOI20_roads) C++17
100 / 100
 586 ms 47556 KB 
#include <bits/stdc++.h>

using i64 = long long;
struct Point {
    i64 x;
    i64 y;
};

constexpr double eps = 1e-9;
struct Segment {
    Point a;
    Point b;

    double eval(i64 x) {
        assert(a.x <= b.x);
        if (a.x == b.x) {
            return a.y;
        } else {
            double ac = a.y * (b.x - x);
            double bc = b.y * (x - a.x);
            return (ac + bc) / (double)(b.x - a.x);
        }
    }
};

constexpr i64 maxC = 20000000;

int main() {
    auto compSegment = [](Segment a, Segment b) -> bool {
        // not cross
        bool isSwapped = false;
        if (a.a.x < b.a.x) {
            std::swap(a, b);
            isSwapped = true;
        }
        i64 s = a.a.y;
        const auto t = b.eval(a.a.x);
        bool u = s - t < eps;
        bool eq = std::abs(s - t) < eps;
        if (eq) {
            return false;
        }
        return u xor isSwapped;
    };
    auto compPoint = [](Point a, Point b) {
        // tokuni iminasi
        return a.x * maxC + a.y < b.x * maxC + b.y;
    };

    int N;
    std::cin >> N;
    std::vector<Segment> segments(N);
    for (auto &[as, bs] : segments) {
        auto &[ax, ay] = as;
        auto &[bx, by] = bs;
        std::cin >> ax >> ay >> bx >> by;
    }
    // std::map<i64, std::vector<int>> addList, eraseList;
    std::map<i64, std::vector<std::pair<int, bool>>> eventList;
    for (int i = 0; i < N; ++i) {
        auto &[as, bs] = segments[i];
        if (as.x > bs.x) {
            std::swap(as, bs);
        }
        if (as.x == bs.x) {
            assert(as.y != bs.y);
            if (as.y > bs.y) {
                std::swap(as, bs);
            }
        }
        eventList[as.x].push_back({i, true});
        eventList[bs.x].push_back({i, false});
    }
    std::map<Point, std::pair<int, bool>, decltype(compPoint)> indexList(compPoint);
    for (int i = 0; i < N; ++i) {
        indexList[segments[i].a] = {i, true};
        indexList[segments[i].b] = {i, false};
    }
    
    std::set<Segment, decltype(compSegment)> segmentSet(compSegment);
    std::vector<Point> safePoint(N);
    std::vector<std::pair<Point, Point>> answer;
    Point safeMi;
    bool isFirst = true;
    for (auto &[xVal, vec] : eventList) {
        std::sort(vec.begin(), vec.end(), [&](auto &a, auto &b) {
            const auto c = a.second ? segments[a.first].a : segments[a.first].b;
            const auto d = b.second ? segments[b.first].a : segments[b.first].b;
            return c.y < d.y;
        });
        for (const auto &[i, type] : vec) {
            if (type) {
                auto itr = segmentSet.insert(segments[i]).first;
                if (itr == segmentSet.begin()) {
                    if (isFirst) {
                        safeMi = segments[i].a;
                        isFirst = false;
                    } else {
                        answer.push_back({segments[i].a, safeMi});
                        safeMi = segments[i].a;
                    }
                    safePoint[i] = segments[i].a;
                    if (segments[i].a.x == segments[i].b.x) {
                        safePoint[i] = segments[i].b;
                        // ok ?
                    }
                    continue;
                }
                --itr;
                answer.push_back({segments[i].a, safePoint[indexList[itr->a].first]});
                safePoint[indexList[itr->a].first] = segments[i].a;
                safePoint[i] = segments[i].a;
                if (segments[i].a.x == segments[i].b.x) {
                    safePoint[i] = segments[i].b;
                    // ok ?
                }
            } else {
                auto itr = segmentSet.find(segments[i]);
                itr = segmentSet.erase(itr);
                if (itr == segmentSet.begin()) {
                    safeMi = segments[i].b;
                    continue;
                }
                --itr;
                safePoint[indexList[itr->a].first] = segments[i].b;
            }
        }
    }

    assert(answer.size() == N - 1);
    for (const auto &[ap, bp] : answer) {
        std::cout << ap.x << ' ' << ap.y << ' ' << bp.x << ' ' << bp.y << std::endl;
    }
}

Compilation message

In file included from /usr/include/c++/10/cassert:44,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:33,
                 from roads.cpp:1:
roads.cpp: In function 'int main()':
roads.cpp:130:26: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<Point, Point> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  130 |     assert(answer.size() == N - 1);
      |            ~~~~~~~~~~~~~~^~~~~~~~

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 162 ms 16060 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 296 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 5 ms 596 KB Output is correct
4 Correct 36 ms 4048 KB Output is correct
5 Correct 76 ms 7792 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 4 ms 596 KB Output is correct
4 Correct 48 ms 4124 KB Output is correct
5 Correct 73 ms 7852 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 304 KB Output is correct
8 Correct 4 ms 724 KB Output is correct
9 Correct 40 ms 5164 KB Output is correct
10 Correct 586 ms 47556 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 4 ms 696 KB Output is correct
4 Correct 36 ms 4116 KB Output is correct
5 Correct 74 ms 7832 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 304 KB Output is correct
8 Correct 4 ms 596 KB Output is correct
9 Correct 39 ms 4144 KB Output is correct
10 Correct 193 ms 18868 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 1 ms 304 KB Output is correct
13 Correct 1 ms 212 KB Output is correct

Subtask #5
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 4 ms 596 KB Output is correct
5 Correct 36 ms 4076 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 4 ms 724 KB Output is correct
9 Correct 41 ms 5188 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Correct 4 ms 596 KB Output is correct
13 Correct 35 ms 4144 KB Output is correct
14 Correct 1 ms 212 KB Output is correct
15 Correct 1 ms 296 KB Output is correct
16 Correct 1 ms 304 KB Output is correct
17 Correct 1 ms 340 KB Output is correct
18 Correct 2 ms 340 KB Output is correct
19 Correct 2 ms 468 KB Output is correct
20 Correct 3 ms 596 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 15 ms 2004 KB Output is correct
23 Correct 15 ms 2008 KB Output is correct
24 Correct 29 ms 3684 KB Output is correct
25 Correct 1 ms 212 KB Output is correct

Subtask #6
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 164 ms 16072 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 4 ms 596 KB Output is correct
6 Correct 35 ms 4052 KB Output is correct
7 Correct 74 ms 7808 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 4 ms 724 KB Output is correct
11 Correct 41 ms 5204 KB Output is correct
12 Correct 569 ms 47548 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 4 ms 612 KB Output is correct
16 Correct 37 ms 4064 KB Output is correct
17 Correct 192 ms 18860 KB Output is correct
18 Correct 1 ms 212 KB Output is correct
19 Correct 1 ms 340 KB Output is correct
20 Correct 1 ms 340 KB Output is correct
21 Correct 1 ms 340 KB Output is correct
22 Correct 1 ms 340 KB Output is correct
23 Correct 2 ms 468 KB Output is correct
24 Correct 3 ms 596 KB Output is correct
25 Correct 1 ms 212 KB Output is correct
26 Correct 16 ms 2016 KB Output is correct
27 Correct 15 ms 2068 KB Output is correct
28 Correct 30 ms 3712 KB Output is correct
29 Correct 219 ms 23868 KB Output is correct
30 Correct 306 ms 30024 KB Output is correct
31 Correct 1 ms 212 KB Output is correct
32 Correct 320 ms 30916 KB Output is correct
33 Correct 312 ms 30932 KB Output is correct
34 Correct 444 ms 40972 KB Output is correct
35 Correct 434 ms 42764 KB Output is correct
36 Correct 380 ms 39740 KB Output is correct