$n leq 100000$个点，$m leq 100000$次询问，每次问删掉一些点后的凸包面积。
不会啦写个20暴力，其实是可以写到50的。当个计算几何板子练习。
1 //#include<iostream> 2 #include<cstring> 3 #include<cstdio> 4 //#include<math.h> 5 //#include<set> 6 //#include<queue> 7 //#include<bitset> 8 //#include<vector> 9 #include<algorithm> 10 #include<stdlib.h> 11 using namespace std; 12 13 #define LL long long 14 int qread() 15 { 16 char c; int s=0,f=1; while ((c=getchar())<'0' || c>'9') (c=='-') && (f=-1); 17 do s=s*10+c-'0'; while ((c=getchar())>='0' && c<='9'); return s*f; 18 } 19 20 //Pay attention to '-' , LL and double of qread!!!! 21 22 int n,m; 23 #define maxn 100011 24 int Abs(int x) {return x>0?x:-x;} 25 struct Poi 26 { 27 int x,y; 28 LL operator * (const Poi &b) const {return 1ll*x*b.y-1ll*y*b.x;} 29 Poi operator - (const Poi &b) const {return (Poi){x-b.x,y-b.y};} 30 bool operator < (const Poi &b) 31 { 32 if (x==0 && y==0) return 0; 33 if (b.x==0 && b.y==0) return 1; 34 Poi c=(Poi){0,0}; 35 LL tmp=(c-(*this))*(c-b); 36 return tmp>0 || (tmp==0 && Abs(x)<Abs(b.x)); 37 } 38 }p[maxn],q[maxn],sta[maxn]; int lq,top; 39 bool vis[maxn]; 40 41 int main() 42 { 43 n=qread(); m=qread(); 44 for (int i=1;i<=n;i++) {p[i].x=qread(); p[i].y=qread();} 45 46 LL s=-1; 47 int K,op; 48 while (m--) 49 { 50 memset(vis,0,sizeof(vis)); 51 K=qread(); 52 while (K--) vis[(qread()+s+n)%n+1]=1; 53 int my=0x3f3f3f3f,id=0; lq=top=0; 54 for (int i=1;i<=n;i++) if (!vis[i]) 55 { 56 q[++lq]=p[i]; 57 if (p[i].y<my) {my=p[i].y; id=lq;} 58 } 59 for (int i=1;i<=lq;i++) if (i!=id) q[i].x-=q[id].x,q[i].y-=q[id].y; q[id].x=q[id].y=0; 60 sort(q+1,q+1+lq); 61 // for (int i=1;i<=lq;i++) cout<<q[i].x<<' '<<q[i].y<<endl;cout<<endl; 62 sta[++top]=q[lq]; 63 for (int i=1;i<=lq;i++) 64 { 65 while (top>1 && (sta[top]-sta[top-1])*(q[i]-sta[top])<=0) top--; 66 sta[++top]=q[i]; 67 } 68 // for (int i=1;i<=top;i++) cout<<sta[i].x<<' '<<sta[i].y<<endl; cout<<endl; 69 s=0; 70 for (int i=1;i<top;i++) s+=sta[i]*sta[i+1]; 71 printf("%lld ",s); 72 } 73 return 0; 74 }