oj.uz

Submission #985636

# Submission time Handle Problem Language Result Execution time Memory
985636 2024-05-18T11:35:21 Z alextodoran Fences (JOI18_fences) C++17
51 / 100
 1000 ms 20852 KB 
/**
 _  _   __  _ _ _  _  _ _
 |a  ||t  ||o    d | |o  |
| __    _| | _ | __|  _ |
| __ |/_  | __  /__\ / _\|

**/

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int N_MAX = 100;
const int V_MAX = N_MAX * 4 + 4;
const ld INF = LLONG_MAX;
const int R = 100;

int N, S;
struct Point {
    ld x, y;
};
ld dist (Point A, Point B) {
    return sqrt((A.x - B.x) * (A.x - B.x) + (A.y - B.y) * (A.y - B.y));
}
struct Segment {
    Point A, B;
    ld len () {
        return dist(A, B);
    }
};
Segment fence[N_MAX + 2];

Point project (Point P, Segment s) {
    if (s.A.x == s.B.x) {
        return Point{s.A.x, P.y};
    } else if (s.A.y == s.B.y) {
        return Point{P.x, s.A.y};
    } else {
        ld mAB = (ld) (s.A.y - s.B.y) / (s.A.x - s.B.x);
        ld mPQ = -1 / mAB;
        Point Q;
        Q.x = (P.y - s.A.y - P.x * mPQ + s.A.x * mAB) / (mAB - mPQ);
        Q.y = P.y + (Q.x - P.x) * mPQ;
        return Q;
    }
}
bool is_inside (Point P, Segment s) {
    return (min(s.A.x, s.B.x) <= P.x && P.x <= max(s.A.x, s.B.x)
         && min(s.A.y, s.B.y) <= P.y && P.y <= max(s.A.y, s.B.y));
}
bool check (Segment s) {
    Point mid = Point{(s.A.x + s.B.x) / 2, (s.A.y + s.B.y) / 2};
    if (-S < mid.x && mid.x < S && -S < mid.y && mid.y < S) {
        return false;
    }
    for (int side = 0; side < 4; side++) {
        if (s.A.y > s.B.y) {
            swap(s.A, s.B);
        }
        if (s.A.y < S && S < s.B.y) {
            ld x;
            if (s.A.x != s.B.x) {
                x = s.A.x + (ld) (s.B.x - s.A.x) * (S - s.A.y) / (s.B.y - s.A.y);
            } else {
                x = s.A.x;
            }
            if (-S < x && x < S) {
                return false;
            }
        }
        swap(s.A.x, s.A.y); s.A.x *= -1;
        swap(s.B.x, s.B.y); s.B.x *= -1;
    }
    return true;
}

Point corner[4];

int V;
Point get_point (int u) {
    if (u <= N * 2) {
        if (u % 2 == 1) {
            return fence[u / 2 + 1].A;
        } else {
            return fence[u / 2].B;
        }
    } else {
        return corner[u - N * 2 - 1];
    }
}
struct Edge {
    int to;
    ld len;
    bool trigo;
};
bool is_trigo (Segment s) {
    return (s.A.x * s.B.y - s.A.y * s.B.x > 0);
}
vector <Edge> out[V_MAX + 2];
void add_edge (int u, int v, Segment s, bool is_fence = false) {
    Point A = s.A, P = s.B, B = get_point(v);
    ld len = (is_fence == false ? s.len() : 0);
    bool trigo = is_trigo(Segment{A, B});
    if (P.x != B.x || P.y != B.y) {
        if (is_trigo(Segment{A, P}) != trigo && is_trigo(Segment{P, B}) != trigo) {
            trigo = !trigo;
        }
    }
    out[u].push_back(Edge{v, len, trigo});
    swap(s.A, s.B); trigo = !trigo;
    out[v].push_back(Edge{u, len, trigo});
}

int get_quad (Point P) {
    if (P.x >= 0 && P.y > 0) {
        return 0;
    } else if (P.x < 0 && P.y >= 0) {
        return 1;
    } else if (P.x <= 0 && P.y < 0) {
        return 2;
    } else {
        return 3;
    }
}

ld min_dist[V_MAX + 2][R * 2 + 2];
bool seen[V_MAX + 2][R * 2 + 2];

struct Path {
    int u;
    int var;
    ld len;
};
bool operator < (const Path &p1, const Path &p2) {
    return p1.len > p2.len;
}

ld answer = LLONG_MAX;

void Dijkstra (int start) {
    priority_queue <Path> q;
    for (int u = 1; u <= V; u++) {
        for (int var = -R; var <= R; var++) {
            min_dist[u][var + R] = INF;
            seen[u][var + R] = false;
        }
    }
    min_dist[start][0 + R] = 0;
    q.push(Path{start, 0, 0});
    while (q.empty() == false) {
        Path p = q.top(); q.pop();
        if (seen[p.u][p.var] == true) {
            continue;
        }
        seen[p.u][p.var] = true;
        if (p.len > answer) {
            continue;
        }
        if (p.u == start && p.var == 4) {
            answer = p.len;
        }
        Point A = get_point(p.u);
        for (Edge e : out[p.u]) {
            Point B = get_point(e.to);
            Path pe; pe.u = e.to; pe.len = p.len + e.len;
            int delta = get_quad(B) - get_quad(A);
            if (e.trigo == true) {
                if (delta < 0) {
                    delta += 4;
                }
            } else {
                if (delta > 0) {
                    delta -= 4;
                }
            }
            pe.var = p.var + delta;
            if (-R <= pe.var && pe.var <= R) {
                if (pe.len < min_dist[pe.u][pe.var + R]) {
                    min_dist[pe.u][pe.var + R] = pe.len;
                    q.push(pe);
                }
            }
        }
    }
}

int main () {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(10);

    cin >> N >> S;
    for (int i = 1; i <= N; i++) {
        cin >> fence[i].A.x >> fence[i].A.y;
        cin >> fence[i].B.x >> fence[i].B.y;
    }
    corner[0] = Point{S, S};
    corner[1] = Point{-S, S};
    corner[2] = Point{-S, -S};
    corner[3] = Point{S, -S};
    for (int c = 0; c < 4; c++) {
        add_edge(N * 2 + 1 + c, N * 2 + 1 + (c + 1) % 4, Segment{corner[c], corner[(c + 1) % 4]});
    }
    V = N * 2 + 4;
    for (int i = 1; i <= N; i++) {
        add_edge(i * 2 - 1, i * 2, fence[i], true);
        for (int j = i + 1; j <= N; j++) {
            Segment A1A2 = Segment{fence[i].A, fence[j].A};
            if (check(A1A2) == true) {
                add_edge(i * 2 - 1, j * 2 - 1, A1A2);
            }
            Segment A1B2 = Segment{fence[i].A, fence[j].B};
            if (check(A1B2) == true) {
                add_edge(i * 2 - 1, j * 2, A1B2);
            }
            Segment B1A2 = Segment{fence[i].B, fence[j].A};
            if (check(B1A2) == true) {
                add_edge(i * 2, j * 2 - 1, B1A2);
            }
            Segment B1B2 = Segment{fence[i].B, fence[j].B};
            if (check(B1B2) == true) {
                add_edge(i * 2, j * 2, B1B2);
            }
        }
    }
    for (int i = 1; i <= N; i++) {
        for (int j = 1; j <= N; j++) {
            if (i != j) {
                Point P = project(fence[i].A, fence[j]);
                Segment AP = Segment{fence[i].A, P};
                if (is_inside(P, fence[j]) == true && check(AP) == true) {
                    add_edge(i * 2 - 1, j * 2 - 1, AP);
                    add_edge(i * 2 - 1, j * 2, AP);
                }
                Point Q = project(fence[i].B, fence[j]);
                Segment BQ = Segment{fence[i].B, Q};
                if (is_inside(Q, fence[j]) == true && check(BQ) == true) {
                    add_edge(i * 2, j * 2 - 1, BQ);
                    add_edge(i * 2, j * 2, BQ);
                }
            }
        }
        for (int c = 0; c < 4; c++) {
            Segment AC = Segment{fence[i].A, corner[c]};
            Segment BC = Segment{fence[i].B, corner[c]};
            if (check(AC) == true) {
                add_edge(i * 2 - 1, N * 2 + 1 + c, AC);
            }
            if (check(BC) == true) {
                add_edge(i * 2, N * 2 + 1 + c, BC);
            }
        }
        for (int c = 0; c < 4; c++) {
            Point P = project(corner[c], fence[i]);
            Segment CP = Segment{corner[c], P};
            if (is_inside(P, fence[i]) == true && check(CP) == true) {
                add_edge(N * 2 + 1 + c, i * 2 - 1, CP);
                add_edge(N * 2 + 1 + c, i * 2, CP);
            }
        }
    }
    for (int u = 1; u <= V; u++) {
        Point A = get_point(u);
        Dijkstra(u);
    }
    cout << answer << "\n";

    return 0;
}

Compilation message

fences.cpp: In function 'int main()':
fences.cpp:200:23: warning: narrowing conversion of 'S' from 'int' to 'ld' {aka 'long double'} [-Wnarrowing]
  200 |     corner[0] = Point{S, S};
      |                       ^
fences.cpp:200:26: warning: narrowing conversion of 'S' from 'int' to 'ld' {aka 'long double'} [-Wnarrowing]
  200 |     corner[0] = Point{S, S};
      |                          ^
fences.cpp:201:23: warning: narrowing conversion of '- S' from 'int' to 'ld' {aka 'long double'} [-Wnarrowing]
  201 |     corner[1] = Point{-S, S};
      |                       ^~
fences.cpp:201:27: warning: narrowing conversion of 'S' from 'int' to 'ld' {aka 'long double'} [-Wnarrowing]
  201 |     corner[1] = Point{-S, S};
      |                           ^
fences.cpp:202:23: warning: narrowing conversion of '- S' from 'int' to 'ld' {aka 'long double'} [-Wnarrowing]
  202 |     corner[2] = Point{-S, -S};
      |                       ^~
fences.cpp:202:27: warning: narrowing conversion of '- S' from 'int' to 'ld' {aka 'long double'} [-Wnarrowing]
  202 |     corner[2] = Point{-S, -S};
      |                           ^~
fences.cpp:203:23: warning: narrowing conversion of 'S' from 'int' to 'ld' {aka 'long double'} [-Wnarrowing]
  203 |     corner[3] = Point{S, -S};
      |                       ^
fences.cpp:203:26: warning: narrowing conversion of '- S' from 'int' to 'ld' {aka 'long double'} [-Wnarrowing]
  203 |     corner[3] = Point{S, -S};
      |                          ^~
fences.cpp:266:15: warning: variable 'A' set but not used [-Wunused-but-set-variable]
  266 |         Point A = get_point(u);
      |               ^

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 348 KB Output is correct
4 Correct 1 ms 348 KB Output is correct
5 Correct 1 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 1 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 1 ms 348 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 0 ms 484 KB Output is correct
15 Correct 1 ms 424 KB Output is correct
16 Correct 0 ms 348 KB Output is correct
17 Correct 1 ms 348 KB Output is correct
18 Correct 0 ms 348 KB Output is correct
19 Correct 0 ms 348 KB Output is correct
20 Correct 1 ms 348 KB Output is correct

Subtask #2
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 348 KB Output is correct
4 Correct 1 ms 348 KB Output is correct
5 Correct 1 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 1 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 1 ms 348 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 0 ms 484 KB Output is correct
15 Correct 1 ms 424 KB Output is correct
16 Correct 0 ms 348 KB Output is correct
17 Correct 1 ms 348 KB Output is correct
18 Correct 0 ms 348 KB Output is correct
19 Correct 0 ms 348 KB Output is correct
20 Correct 1 ms 348 KB Output is correct
21 Correct 1 ms 600 KB Output is correct
22 Correct 1 ms 348 KB Output is correct
23 Correct 1 ms 348 KB Output is correct
24 Correct 1 ms 344 KB Output is correct
25 Correct 1 ms 484 KB Output is correct
26 Correct 1 ms 348 KB Output is correct
27 Correct 1 ms 348 KB Output is correct
28 Correct 1 ms 348 KB Output is correct
29 Correct 1 ms 348 KB Output is correct
30 Correct 1 ms 348 KB Output is correct
31 Correct 1 ms 348 KB Output is correct
32 Correct 1 ms 348 KB Output is correct
33 Correct 1 ms 348 KB Output is correct
34 Correct 1 ms 344 KB Output is correct
35 Correct 1 ms 344 KB Output is correct
36 Correct 1 ms 348 KB Output is correct
37 Correct 1 ms 348 KB Output is correct
38 Correct 1 ms 348 KB Output is correct
39 Correct 1 ms 348 KB Output is correct
40 Correct 1 ms 360 KB Output is correct
41 Correct 1 ms 348 KB Output is correct
42 Correct 1 ms 348 KB Output is correct
43 Correct 2 ms 604 KB Output is correct

Subtask #3
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 348 KB Output is correct
4 Correct 1 ms 348 KB Output is correct
5 Correct 1 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 1 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 1 ms 348 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 0 ms 484 KB Output is correct
15 Correct 1 ms 424 KB Output is correct
16 Correct 0 ms 348 KB Output is correct
17 Correct 1 ms 348 KB Output is correct
18 Correct 0 ms 348 KB Output is correct
19 Correct 0 ms 348 KB Output is correct
20 Correct 1 ms 348 KB Output is correct
21 Correct 1 ms 600 KB Output is correct
22 Correct 1 ms 348 KB Output is correct
23 Correct 1 ms 348 KB Output is correct
24 Correct 1 ms 344 KB Output is correct
25 Correct 1 ms 484 KB Output is correct
26 Correct 1 ms 348 KB Output is correct
27 Correct 1 ms 348 KB Output is correct
28 Correct 1 ms 348 KB Output is correct
29 Correct 1 ms 348 KB Output is correct
30 Correct 1 ms 348 KB Output is correct
31 Correct 1 ms 348 KB Output is correct
32 Correct 1 ms 348 KB Output is correct
33 Correct 1 ms 348 KB Output is correct
34 Correct 1 ms 344 KB Output is correct
35 Correct 1 ms 344 KB Output is correct
36 Correct 1 ms 348 KB Output is correct
37 Correct 1 ms 348 KB Output is correct
38 Correct 1 ms 348 KB Output is correct
39 Correct 1 ms 348 KB Output is correct
40 Correct 1 ms 360 KB Output is correct
41 Correct 1 ms 348 KB Output is correct
42 Correct 1 ms 348 KB Output is correct
43 Correct 2 ms 604 KB Output is correct
44 Correct 138 ms 5368 KB Output is correct
45 Correct 204 ms 4184 KB Output is correct
46 Correct 192 ms 3612 KB Output is correct
47 Correct 168 ms 3096 KB Output is correct
48 Correct 166 ms 5468 KB Output is correct
49 Correct 213 ms 4440 KB Output is correct
50 Correct 212 ms 4116 KB Output is correct
51 Correct 177 ms 3032 KB Output is correct
52 Correct 195 ms 3700 KB Output is correct
53 Correct 158 ms 3676 KB Output is correct
54 Correct 160 ms 3980 KB Output is correct
55 Correct 237 ms 4096 KB Output is correct
56 Correct 226 ms 4292 KB Output is correct
57 Correct 204 ms 3676 KB Output is correct
58 Correct 207 ms 3812 KB Output is correct
59 Correct 223 ms 3884 KB Output is correct
60 Correct 244 ms 4112 KB Output is correct
61 Correct 217 ms 4196 KB Output is correct
62 Correct 1 ms 600 KB Output is correct
63 Correct 1 ms 508 KB Output is correct
64 Correct 327 ms 4576 KB Output is correct
65 Correct 272 ms 2992 KB Output is correct
66 Correct 171 ms 2904 KB Output is correct
67 Execution timed out 1074 ms 20852 KB Time limit exceeded
68 Halted 0 ms 0 KB -