寄蒜几盒？

 

 1 struct Poi {
 2     LL x, y;
 3     Poi() {}
 4     Poi(LL X, LL Y)
 5         : x(X), y(Y) {}
 6     bool operator==(const Poi& R) const {
 7         return (x == R.x) && (y == R.y);
 8     }
 9     Poi operator+(const Poi& R) const {
10         return Poi(x + R.x, y + R.y);
11     }
12     Poi operator-(const Poi& R) const {
13         return Poi(x - R.x, y - R.y);
14     }
15     LL operator&(const Poi& R) const {
16         return x * R.x + y * R.y;
17     }
18     LL operator*(const Poi& R) const {
19         return x * R.y - y * R.x;
20     }
21     inline void read() {
22         ::read(x);
23         ::read(y);
24     }
25 };
26 struct Line {
27     Poi A, B;
28     Line() {}
29     Line(Poi a, Poi b)
30         : A(a), B(b) {}
31 };
32 inline LL dis2(Poi A, Poi B) {
33     return (A.x - B.x) * (A.x - B.x) + (A.y - B.y) * (A.y - B.y);
34 }
35 
36 inline bool ConvexCmp(const Poi& A, const Poi& B) {
37     if(A.x != B.x)
38         return A.x < B.x;
39     return A.y < B.y;
40 }
41 void GetConvex(Poi* a, int n, Poi* p, int& tot) {
42     std::sort(a, a + n, ConvexCmp);
43     p[0] = a[0];
44     tot = 1;
45     for(int i = 1; i < n; i++) {
46         while((tot > 1 && (p[tot - 1] - p[tot - 2]) * (a[i] - p[tot - 1]) <= 0)) {
47             --tot;
48         }
49         p[tot++] = a[i];
50     }
51     int temp = tot;
52     for(int i = n - 2; i >= 0; i--) {
53         while((tot > temp && (p[tot - 1] - p[tot - 2]) * (a[i] - p[tot - 1]) <= 0)) {
54             --tot;
55         }
56         p[tot++] = a[i];
57     }
58     --tot;
59     return;
60 }

总模板