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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. struct Point {
  5.     long double x, y;
  6. };
  7.  
  8. int main() {
  9.     ios::sync_with_stdio(false);
  10.     cin.tie(nullptr);
  11.  
  12.     long double W, H;
  13.     cin >> W >> H; // dimenzije nisu potrebne u rešenju
  14.  
  15.     int n;
  16.     cin >> n;
  17.  
  18.     vector<Point> p(n);
  19.     for (int i = 0; i < n; ++i) cin >> p[i].x >> p[i].y;
  20.  
  21.     const long double PI = acosl(-1.0L);
  22.     const long double TWO_PI = 2.0L * PI;
  23.     const long double EPS = 1e-12L;
  24.  
  25.     vector<long double> ang;
  26.     ang.reserve(max(0, n - 1));
  27.  
  28.     for (int i = 0; i + 1 < n; ++i) {
  29.         long double dx = p[i + 1].x - p[i].x;
  30.         long double dy = p[i + 1].y - p[i].y;
  31.         long double a = atan2l(dy, dx);   // [-pi, pi]
  32.         if (a < 0) a += TWO_PI;           // [0, 2pi)
  33.         ang.push_back(a);
  34.     }
  35.  
  36.     sort(ang.begin(), ang.end());
  37.     int m = (int)ang.size();
  38.  
  39.     long double bestGap = 0.0L;
  40.     for (int i = 0; i + 1 < m; ++i) {
  41.         bestGap = max(bestGap, ang[i + 1] - ang[i]);
  42.     }
  43.     bestGap = max(bestGap, ang[0] + TWO_PI - ang[m - 1]);
  44.  
  45.     if (bestGap >= PI - EPS) cout << "DA\n";
  46.     else cout << "NE\n";
  47.  
  48.     return 0;
  49. }
Success #stdin #stdout 0s 5320KB
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DA
https://ideone.com/ToCUum
language:
C++ (gcc 8.3)
created:
6 hours ago
visibility:
public

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