FJ省队集训DAY2 T2

  1 #include<cstdio>
  2 #include<iostream>
  3 #include<cmath>
  4 #include<cstring>
  5 #include<algorithm>
  6 #define MAXN 2005
  7 struct Point{
  8     double x,y;
  9     double p,ang;
 10     int id;
 11 }p[MAXN],Cur[MAXN];
 12 double P[MAXN],T[MAXN * 4];
 13 int n,m,rk[MAXN],s[MAXN],f[MAXN][MAXN];
 14 int read(){
 15     int t=0,f=1;char ch=getchar();
 16     while (ch<‘0‘||ch>‘9‘){if (ch==‘-‘)f=-1;ch=getchar();}
 17     while (‘0‘<=ch&&ch<=‘9‘){t=t*10+ch-‘0‘;ch=getchar();}
 18     return t*f;
 19 }
 20 bool cmp(Point p1,Point p2){
 21     return p1.ang<p2.ang;
 22 }
 23 void build (int k,int l,int r){
 24     if (l==r) {T[k]=1-P[Cur[l].id];return;}
 25     int mid=(l+r)>>1;
 26     build(k*2,l,mid);
 27     build(k*2+1,mid+1,r);
 28     T[k]=T[k*2]*T[k*2+1];
 29 }
 30 double query(int k,int l,int r,int x,int y){
 31     if (y<l||x>r) return 1.0;
 32     if (l==x&&r==y) return T[k];
 33     int mid=(l+r)>>1;
 34     if (y<=mid) return query(k*2,l,mid,x,y);
 35     else
 36     if (x>mid) return query(k*2+1,mid+1,r,x,y);
 37     else return query(k*2,l,mid,x,mid)*query(k*2+1,mid+1,r,mid+1,y);
 38 }
 39 void init(){
 40     n=read();m=read();
 41     for (int i=1;i<=n;i++)
 42       scanf("%lf%lf",&p[i].x,&p[i].y),p[i].id=i;
 43     for (int i=n+1;i<=n+m;i++)
 44       scanf("%lf%lf%lf",&p[i].x,&p[i].y,&P[i]),p[i].id=i;
 45     for (int i=1;i<=n+m;i++)
 46      p[i].ang=atan2(p[i].y,p[i].x);   
 47 }
 48 void add(int pos){
 49     for (;pos<=n+m;pos+=(pos)&(-pos)) s[pos]++;
 50 }
 51 int sum(int pos){
 52     int res=0;
 53     for (;pos;pos-=(pos)&(-pos)) res+=s[pos];
 54     return res;
 55 }
 56 void Sort(int mid){
 57     int tot=0;
 58     for (int i=0;i<=n+m;i++)
 59      if (i!=mid) Cur[++tot]=p[i],Cur[tot].ang=atan2(Cur[tot].y-p[mid].y,Cur[tot].x-p[mid].x);
 60     std::sort(Cur+1,Cur+1+tot,cmp);
 61     for (int i=1;i<=tot;i++) rk[Cur[i].id]=i;
 62 }
 63 int range(int l,int r){
 64     if (l<=r) return sum(r)-sum(l-1);
 65     return sum(n+m)-sum(l-1)+sum(r);
 66 }
 67 void solve(){
 68     std::sort(p+1,p+1+n+m,cmp);
 69     for (int i=1;i<=n+m+1;i++)
 70      if (p[i].id>n){
 71             Sort(i);
 72             for (int j=0;j<=n+m;j++) s[j]=0;
 73             for (int j=i+1;j<=n+m+1;j++){
 74                 if (p[j].id<=n&&p[j].id) add(rk[p[j].id]);
 75                 f[p[i].id][p[j].id]=std::max(0,range(rk[p[j].id],rk[0]));
 76             }
 77             for (int j=0;j<=n+m;j++) s[j]=0;
 78             for (int j=i-1;j;j--){
 79                 if (p[j].id<=n&&p[j].id) add(rk[p[j].id]);
 80                 f[p[i].id][p[j].id]=std::max(0,range(rk[0],rk[p[j].id])); 
 81             }
 82      }
 83 }
 84 double ask(int l,int r){
 85     if (l>r) return query(1,1,n+m-1,l,n+m-1)*query(1,1,n+m-1,1,r-1);
 86     else return query(1,1,n+m-1,l,r-1);
 87 }
 88 void linear(){
 89     double ans=0.0;
 90     int tot=0;
 91     for (int i=1;i<=n+m;i++)
 92      if (p[i].id>n){
 93             tot=0;
 94             for (int j=1;j<=n+m;j++)
 95              if (i!=j) Cur[++tot]=p[j],Cur[tot].ang=atan2(p[j].y-p[i].y,p[j].x-p[i].x);
 96             std::sort(Cur+1,Cur+1+tot,cmp);
 97             build(1,1,tot);
 98             for (int j=1,Pp=1;j<=tot;j++){
 99                 for(;(Cur[j].x - p[i].x) * (Cur[Pp].y - p[i].y) - (Cur[j].y - p[i].y) * (Cur[Pp].x - p[i].x) > 0;) Pp=Pp%tot+1;
100                 if (Cur[j].id>n){
101                     double pr=ask(Pp,j)*P[p[i].id]*P[Cur[j].id];
102                     if (p[i].x * Cur[j].y - p[i].y * Cur[j].x < 0) 
103                         ans -= pr * f[p[i].id][Cur[j].id]; else
104                         ans += pr * f[p[i].id][Cur[j].id];
105                      }
106                 }
107             } 
108     printf("%.9lf\n",ans);
109 }
110 int main(){
111     init();
112     solve();
113     linear();
114 }