제출 #961071

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
961071		Pety	Kućice (COCI21_kucice)	C++14	110 / 110	89 ms	604 KiB

Main

#include <bits/stdc++.h>
 
using namespace std;
 
const int N = 1e6+2;
using ll = long long;
const int mod = 1e9 + 7;

int n;
struct point {
  ll x, y;
  point operator - (const point &other) const {
    return {x - other.x, y - other.y};
  }
};
point p[1002];

ll ccw (point a, point b) {
  return a.x * b.y - a.y * b.x;
}

bool cmp (point a, point b) {
  if ((a.x > 0) != (b.x > 0))
    return a.x < b.x;
  return ccw(a, b) > 0;
}
ll pw[1002];

int main () 
{
  ios_base::sync_with_stdio(false);
  cin.tie(0); cout.tie(0);
  cin >> n;
  pw[0] = 1;
  for (int i = 1; i <= n; i++) {
    cin >> p[i].x >> p[i].y;
    pw[i] = 2ll * pw[i - 1] % mod;
  }
  ll ans = 0;
  for (int i = 1; i <= n; i++) {
    vector<point>v;
    for (int j = 1; j <= n; j++)
      if (j != i)
        v.push_back(p[j] - p[i]);
    sort(v.begin(), v.end(), cmp);
    int j = 0;
    ll x = 0;
    for (int i = 0; i < n - 1; i++) {
      while (ccw(v[i], v[(j + 1) % (n - 1)]) > 0)
        j++;
      x = (x + pw[(j - i + (n - 1)) % (n - 1)]) % mod;
    }
    x = pw[n] - x;
    if (x < 0) x += mod;
    ans += x;
    if (ans >= mod) ans %= mod;
  }
  cout << (ans-n + mod) % mod;
  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 30 / 30
• Subtask 3: 10 / 10
• Subtask 4: 30 / 30
• Subtask 5: 30 / 30