oj.uz

Submission #20993

# Submission time Handle Problem Language Result Execution time Memory
20993 2017-03-27T09:41:36 Z model_code Relay (COI16_relay) C++11
100 / 100
 119 ms 9916 KB 
// Autor: Frane Kurtovic

#include <cstdio>
#include <vector>
#include <set>
#include <cassert>

using namespace std;

#define x first
#define y second

typedef long long llint;
typedef pair<llint, llint> point;

point operator+(const point &l, const point &r) {
  return point(l.first+r.first, l.second+r.second);
}

point operator-(const point &l, const point &r) {
  return point(l.first-r.first, l.second-r.second);
}

llint ccw(const point &a, const point &b, const point &c) {
  point p1 = b-a;
  point p2 = c-a;
  return p1.first*p2.second - p1.second*p2.first;
}

bool out(const point &s, const point &e, const point &P) {
  return ccw(s, e, P) < 0;
}

bool out_or_on(const point &s, const point &e, const point &P) {
  return ccw(s, e, P) <= 0;
}

const int MAX_N = 100010;
point ships[MAX_N]; int n;
vector <point> poly; int m; // u ccw smjeru zadan

pair<int, int> find_tangent(const point &P) {
  point prev = poly[m-1];
  int left_t = -1, right_t = -1;
  for (int i = 0; i < m; i++) {
    point curr = poly[i];
    point next = poly[i+1];

    if (out(prev, curr, P) && !out(curr, next, P)) {
      // desna tangenta
      assert (right_t == -1);
      right_t = i;
    }

    if (!out(prev, curr, P) && out(curr, next, P)) {
      // lijeva tangenta
      assert (left_t == -1);
      left_t = i;
    }
    prev = curr;
  }
  assert (left_t != -1);
  assert (right_t != -1);
  return {left_t, right_t};
}

int prev(int x) {
  if (x == 0) return m-1;
  return x-1;
}

int next(int x) {
  return (x+1)%m;
}

int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%lld %lld", &ships[i].x, &ships[i].y);
  }
  scanf("%d", &m);
  for (int i = 0; i < m; i++) {
    point curr;
    scanf("%lld %lld", &curr.x, &curr.y);
    poly.push_back(curr);
  }
  poly.push_back(poly.front());

  point P = ships[0];
  auto tangents = find_tangent(P);

  int l_tangent = tangents.first, r_tangent = tangents.second;
  point l = P, r = P; // tocka iz koje ide najlijevija tangenta
  set <point> s;
  for (int i = 1; i < n; i++) {
    point T = ships[i];
    if (ccw(P, poly[tangents.first], ships[i]) >= 0 || ccw(P, poly[tangents.second], ships[i]) <= 0) {
      s.insert(ships[i]);
    } else if (ccw(P, poly[tangents.first], ships[i]) < 0 &&
        ccw(P, poly[tangents.second], ships[i]) > 0 &&
        ccw(poly[tangents.first], poly[tangents.second], ships[i]) <= 0) {
      // izmedju dvije tangente i otoka
      s.insert(ships[i]);
    }

    if (ccw(P, poly[tangents.first], T) >= 0) {
      // strana lijeve tangente
      while(true) {
        int next_e = prev(l_tangent);
        if (out_or_on(poly[next_e], poly[l_tangent], T)) {
          l_tangent = next_e;
          l = T;
        } else {
          break;
        }
      }
      if (ccw(l, poly[l_tangent], T) > 0) {
        l = T;
      }
    }

    if (ccw(P, poly[tangents.second], T) <= 0) {
      // strana desne tangente
      while(true) {
        int next_e = next(r_tangent);
        if (out_or_on(poly[r_tangent], poly[next_e], T)) {
          r_tangent = next_e;
          r = T;
        } else {
          break;
        }
      }
      if (ccw(r, poly[r_tangent], T) < 0) {
        r = T;
      }
    }
  }

  for (int i = 0; i < n; i++) {
    point p = ships[i];
    if (ccw(l, poly[l_tangent], p) >= 0) {
      s.insert(p);
    } else if (ccw(l, P, p) >= 0 && ccw(P, poly[l_tangent], p) >= 0) {
      s.insert(p);
    }

    if (ccw(r, poly[r_tangent], p) <= 0) {
      s.insert(p);
    } else if (ccw(P, r, p) >= 0 && ccw(poly[r_tangent], P, p) >= 0) {
      s.insert(p);
    }
  }
  s.erase(P);
  printf("%lu\n", s.size());
  return 0;
}

Compilation message

relay.cpp: In function 'int main()':
relay.cpp:77:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &n);
                  ^
relay.cpp:79:49: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld %lld", &ships[i].x, &ships[i].y);
                                                 ^
relay.cpp:81:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &m);
                  ^
relay.cpp:84:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld %lld", &curr.x, &curr.y);
                                         ^

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2740 KB Output is correct
2 Correct 0 ms 2740 KB Output is correct
3 Correct 0 ms 2740 KB Output is correct
4 Correct 0 ms 2740 KB Output is correct
5 Correct 0 ms 2740 KB Output is correct
6 Correct 0 ms 2740 KB Output is correct
7 Correct 0 ms 2740 KB Output is correct
8 Correct 0 ms 2740 KB Output is correct
9 Correct 0 ms 2740 KB Output is correct
10 Correct 0 ms 2740 KB Output is correct

Subtask #2
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2740 KB Output is correct
2 Correct 0 ms 2740 KB Output is correct
3 Correct 0 ms 2740 KB Output is correct
4 Correct 0 ms 2740 KB Output is correct
5 Correct 0 ms 2740 KB Output is correct
6 Correct 0 ms 2740 KB Output is correct
7 Correct 0 ms 2740 KB Output is correct
8 Correct 0 ms 2740 KB Output is correct
9 Correct 0 ms 2740 KB Output is correct
10 Correct 0 ms 2740 KB Output is correct
11 Correct 0 ms 2880 KB Output is correct
12 Correct 0 ms 2880 KB Output is correct
13 Correct 0 ms 2880 KB Output is correct
14 Correct 0 ms 2880 KB Output is correct
15 Correct 0 ms 2880 KB Output is correct
16 Correct 0 ms 2880 KB Output is correct
17 Correct 0 ms 2880 KB Output is correct
18 Correct 3 ms 3012 KB Output is correct
19 Correct 0 ms 2880 KB Output is correct
20 Correct 0 ms 2880 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2740 KB Output is correct
2 Correct 0 ms 2740 KB Output is correct
3 Correct 0 ms 2740 KB Output is correct
4 Correct 0 ms 2740 KB Output is correct
5 Correct 0 ms 2740 KB Output is correct
6 Correct 0 ms 2740 KB Output is correct
7 Correct 0 ms 2740 KB Output is correct
8 Correct 0 ms 2740 KB Output is correct
9 Correct 0 ms 2740 KB Output is correct
10 Correct 0 ms 2740 KB Output is correct
11 Correct 36 ms 5380 KB Output is correct
12 Correct 43 ms 5380 KB Output is correct
13 Correct 59 ms 8020 KB Output is correct
14 Correct 46 ms 5380 KB Output is correct
15 Correct 46 ms 4324 KB Output is correct
16 Correct 49 ms 4324 KB Output is correct
17 Correct 83 ms 8020 KB Output is correct
18 Correct 89 ms 7888 KB Output is correct
19 Correct 79 ms 7756 KB Output is correct
20 Correct 53 ms 5644 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2740 KB Output is correct
2 Correct 0 ms 2740 KB Output is correct
3 Correct 0 ms 2740 KB Output is correct
4 Correct 0 ms 2740 KB Output is correct
5 Correct 0 ms 2740 KB Output is correct
6 Correct 0 ms 2740 KB Output is correct
7 Correct 0 ms 2740 KB Output is correct
8 Correct 0 ms 2740 KB Output is correct
9 Correct 0 ms 2740 KB Output is correct
10 Correct 0 ms 2740 KB Output is correct
11 Correct 0 ms 2880 KB Output is correct
12 Correct 0 ms 2880 KB Output is correct
13 Correct 0 ms 2880 KB Output is correct
14 Correct 0 ms 2880 KB Output is correct
15 Correct 0 ms 2880 KB Output is correct
16 Correct 0 ms 2880 KB Output is correct
17 Correct 0 ms 2880 KB Output is correct
18 Correct 3 ms 3012 KB Output is correct
19 Correct 0 ms 2880 KB Output is correct
20 Correct 0 ms 2880 KB Output is correct
21 Correct 36 ms 5380 KB Output is correct
22 Correct 43 ms 5380 KB Output is correct
23 Correct 59 ms 8020 KB Output is correct
24 Correct 46 ms 5380 KB Output is correct
25 Correct 46 ms 4324 KB Output is correct
26 Correct 49 ms 4324 KB Output is correct
27 Correct 83 ms 8020 KB Output is correct
28 Correct 89 ms 7888 KB Output is correct
29 Correct 79 ms 7756 KB Output is correct
30 Correct 53 ms 5644 KB Output is correct
31 Correct 73 ms 7376 KB Output is correct
32 Correct 79 ms 7376 KB Output is correct
33 Correct 89 ms 8332 KB Output is correct
34 Correct 69 ms 8596 KB Output is correct
35 Correct 76 ms 7012 KB Output is correct
36 Correct 76 ms 6484 KB Output is correct
37 Correct 116 ms 8728 KB Output is correct
38 Correct 119 ms 9916 KB Output is correct
39 Correct 63 ms 6352 KB Output is correct
40 Correct 69 ms 6616 KB Output is correct