제출 #588500

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
588500		MilosMilutinovic	Planine (COCI21_planine)	C++14	110 / 110	244 ms	54596 KiB

Main

/**
 *    author:  wxhtzdy
 *    created: 03.07.2022 13:33:18
**/
#include <bits/stdc++.h>

using namespace std;

string to_string(string s) {
  return '"' + s + '"';
}
string to_string(const char* s) {
  return to_string((string) s);
}
string to_string(bool b) {
  return (b ? "true" : "false");
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

struct Frac {
  long long p, q;
};

bool operator < (Frac a, Frac b) {
  return a.p * b.q < b.p * a.q;
}

struct Point {
  int x, y;
};

int orientation(Point a, Point b, Point c) {
  long long prod = (b.y - a.y) * 1LL * (c.x - b.x)
                   - (b.x - a.x) * 1LL * (c.y - b.y);
  return (prod == 0 ? 0 : (prod > 0 ? 1 : -1));
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);  
  int n, h;
  cin >> n >> h;
  vector<Point> a(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i].x >> a[i].y;
  }
  vector<Point> L(n);
  {
    vector<Point> hull(1, a[0]);
    for (int i = 1; i < n; i++) {
      while ((int) hull.size() > 1 && orientation(hull.rbegin()[1], hull.rbegin()[0], a[i]) == -1) {
        hull.pop_back();  
      }
      L[i] = hull.back();
      hull.push_back(a[i]);  
    }
  }
  vector<Point> R(n);
  {
    vector<Point> hull(1, a[n - 1]);
    for (int i = n - 2; i >= 0; i--) {
      while ((int) hull.size() > 1 && orientation(a[i], hull.rbegin()[0], hull.rbegin()[1]) == -1) {
        hull.pop_back();  
      }
      R[i] = hull.back();
      hull.push_back(a[i]);  
    }
  }                         
  for (int i = 2; i < n - 1; i += 2) {
    debug(i, L[i].x, L[i].y);
    debug(i, R[i].x, R[i].y);
  }
  vector<pair<Frac, Frac>> ev;
  for (int i = 2; i < n - 1; i += 2) {
    Frac fL, fR;
    fL.p = a[i].x * 1LL * (L[i].y - a[i].y) + (h - a[i].y) * 1LL * (L[i].x - a[i].x);
    fL.q = L[i].y - a[i].y;
    fR.p = a[i].x * 1LL * (R[i].y - a[i].y) + (h - a[i].y) * 1LL * (R[i].x - a[i].x);
    fR.q = R[i].y - a[i].y;
    ev.emplace_back(fL, fR);
  }
  sort(ev.begin(), ev.end(), [&](pair<Frac, Frac> a, pair<Frac, Frac> b) {
    return a.second < b.second;
  });
  Frac lst;
  int ans = 0;
  for (int i = 0; i < (int) ev.size(); i++) {
    if (i == 0 || lst < ev[i].first) {
      ans += 1;
      lst = ev[i].second;      
    }
  }
  cout << ans << '\n';                 
  return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

Main.cpp: In function 'int main()':
Main.cpp:45:20: warning: statement has no effect [-Wunused-value]
   45 | #define debug(...) 42
      |                    ^~
Main.cpp:98:5: note: in expansion of macro 'debug'
   98 |     debug(i, L[i].x, L[i].y);
      |     ^~~~~
Main.cpp:45:20: warning: statement has no effect [-Wunused-value]
   45 | #define debug(...) 42
      |                    ^~
Main.cpp:99:5: note: in expansion of macro 'debug'
   99 |     debug(i, R[i].x, R[i].y);
      |     ^~~~~

• Subtask 1: 20 / 20
• Subtask 2: 30 / 30
• Subtask 3: 60 / 60