답안 #20993 :: oj.uz

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
20993	2017-03-27T09:41:36 Z	model_code	Relay (COI16_relay)	C++11	100 / 100	119 ms	9916 KB

relay

// 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

#	결과	메모리	Grader output
1	Correct	2740 KB	Output is correct
2	Correct	2740 KB	Output is correct
3	Correct	2740 KB	Output is correct
4	Correct	2740 KB	Output is correct
5	Correct	2740 KB	Output is correct
6	Correct	2740 KB	Output is correct
7	Correct	2740 KB	Output is correct
8	Correct	2740 KB	Output is correct
9	Correct	2740 KB	Output is correct
10	Correct	2740 KB	Output is correct

Subtask #2
19.0 / 19.0

#	결과	실행 시간	메모리	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

#	결과	실행 시간	메모리	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

#	결과	실행 시간	메모리	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

답안 #20993

Compilation message

Subtask #1 18.0 / 18.0

Subtask #2 19.0 / 19.0

Subtask #3 20.0 / 20.0

Subtask #4 43.0 / 43.0

Subtask #1
18.0 / 18.0

Subtask #2
19.0 / 19.0

Subtask #3
20.0 / 20.0

Subtask #4
43.0 / 43.0