BZOJ 2244: [SDOI2011]拦截导弹 [CDQ分治 树状数组]

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
typedef long long ll;
const int N=5e4+5,INF=1e9;
inline int read(){
    char c=getchar();int x=0,f=1;
    while(c<‘0‘||c>‘9‘){if(c==‘-‘)f=-1;c=getchar();}
    while(c>=‘0‘&&c<=‘9‘){x=x*10+c-‘0‘;c=getchar();}
    return x*f;
}
int n,m;
int mp[N];
void iniMP(){
    sort(mp+1,mp+1+m);
    int p=0;
    mp[++p]=mp[1];
    for(int i=2;i<=m;i++) if(mp[i]!=mp[i-1]) mp[++p]=mp[i];
    m=p;
}
int Bin(int v){
    int l=1,r=m;
    while(l<=r){
        int mid=(l+r)>>1;
        if(v==mp[mid]) return mid;
        else if(v<mp[mid]) r=mid-1;
        else l=mid+1;
    }
    return 0;
}
int c[N],mark[N],CL;double cnt[N];
inline int lowbit(int x){return x&-x;}
inline void upd(int p,int f,double g){
    for(;p<=m;p+=lowbit(p)){
        if(mark[p]!=CL) mark[p]=CL,c[p]=f,cnt[p]=g;
        else if(c[p]<f) c[p]=f,cnt[p]=g;
        else if(c[p]==f) cnt[p]+=g;
    }
}
inline void que(int p,int &f,double &g){
    for(;p;p-=lowbit(p)) if(mark[p]==CL){
        if(c[p]>f)  f=c[p],g=cnt[p];
        else if(c[p]==f) g+=cnt[p];
    }
}
struct Data{
    int x,y,id;
}a[N];
int ref[N];
inline bool cmpX(int p,int q){
    return a[p].x==a[q].x ? a[p].id<a[q].id : a[p].x<a[q].x;
}
int F[2][N];double G[2][N];
void CDQ(int l,int r,int tp){
    if(l==r) return;
    int mid=(l+r)>>1;
    CDQ(l,mid,tp);
    for(int i=l;i<=r;i++) ref[i]=i;
    sort(ref+l,ref+r+1,cmpX);
    int *f=F[tp]; double *g=G[tp];
    CL++;
    for(int i=l;i<=r;i++){
        int _=i;i=ref[i];
        if(a[i].id<=mid) upd(a[i].y,f[a[i].id],g[a[i].id]);
        else{
            int v=0;double sum=0;que(a[i].y,v,sum);
            v++;
            if(v>f[a[i].id]) f[a[i].id]=v,g[a[i].id]=sum;
            else if(v==f[a[i].id]) g[a[i].id]+=sum;
        }
        i=_;
    }
    CDQ(mid+1,r,tp);
}
int main(){
    freopen("in","r",stdin);
    n=read();
    for(int i=1;i<=n;i++) a[i].x=read(),mp[++m]=a[i].y=read();
    iniMP();
    for(int i=1;i<=n;i++) a[i].y=Bin(a[i].y);
    for(int i=1;i<=n;i++) F[0][i]=F[1][i]=G[0][i]=G[1][i]=1;
    reverse(a+1,a+1+n);
    for(int i=1;i<=n;i++) a[i].id=i;
    CDQ(1,n,0);
    //for(int i=1;i<=n;i++) printf("F0  %d %d %d  %d %lf\n",i,a[i].x,a[i].y,F[0][i],G[0][i]);
//puts("---");
    reverse(a+1,a+1+n);
    for(int i=1;i<=n;i++) a[i].y=m-a[i].y+1,a[i].x=INF-a[i].x,a[i].id=i;
    CDQ(1,n,1);
    //for(int i=1;i<=n;i++) printf("F1  %d %d %d  %d %lf\n",i,a[i].x,a[i].y,F[1][i],G[1][i]);

    for(int i=1;i<=n/2;i++) swap(F[0][i],F[0][n-i+1]),swap(G[0][i],G[0][n-i+1]);
    int ans=0;double tot=0;
    for(int i=1;i<=n;i++) ans=max(ans,F[0][i]);
    for(int i=1;i<=n;i++) if(F[0][i]==ans) tot+=G[0][i];//printf("tot %lf\n",tot);
    printf("%d\n",ans);
    for(int i=1;i<=n;i++){
        if(F[0][i]+F[1][i]-1!=ans) printf("%.5lf ",0.0);
        else printf("%.5lf ",G[0][i]*G[1][i]/tot);
    }
}