P3810 【模板】三維偏序（陌上花開）

模板題而已

不會cdq的看這裡：cdq分治：從分治到套娃

一維排序，二維cdq，三維樹狀陣列

#include<algorithm>
#include<iostream>
#include<cstdio>
using namespace std;
int n1,n2,k;
const int N=100010,K=200010;
int ans[N],tr[K];
struct treAKer{int a,b,c,num,ans;}a[N],b[N];
int my_a(const treAKer &a,const treAKer &b)
{
    if(a.a==b.a)
    {
        if(a.b==b.b)return a.c<b.c;
        return a.b<b.b;
    }
    return a.a<b.a;
}
int my_b(const treAKer &a,const treAKer &b)
{
    if(a.b==b.b)return a.c<b.c;
    return a.b<b.b;
}
int lowbit(int x){return x&(-x);}
int ask(int x)
{
	int ans=0;
	for(;x;x-=lowbit(x))ans+=tr[x];
	return ans;
}
void change(int x,int v){for(;x<=k;x+=lowbit(x))tr[x]+=v;}
void cdq(int l,int r)
{
	if(l==r)return;
	int mid=(l+r)>>1;
	cdq(l,mid);cdq(mid+1,r);sort(b+l,b+mid+1,my_b);sort(b+mid+1,b+r+1,my_b);
	int i=l,j=mid+1;
	for(;j<=r;++j)
	{
		while(i<=mid&&b[i].b<=b[j].b)change(b[i].c,b[i].num),++i;
		b[j].ans+=ask(b[j].c);
	}
	for(int k=l;k<=i-1;++k)change(b[k].c,-b[k].num);
}
int main()
{
	cin>>n1>>k;
	for(int i=1;i<=n1;++i)scanf("%d%d%d",&a[i].a,&a[i].b,&a[i].c);
	sort(a+1,a+n1+1,my_a);
	for(int i=1,now=0;i<=n1;++i)
	{
		++now;
		if(a[i].a!=a[i+1].a||a[i].b!=a[i+1].b||a[i].c!=a[i+1].c)b[++n2]=a[i],b[n2].num=now,now=0;
	}
	cdq(1,n2);
    for(int i=1;i<=n2;++i)ans[b[i].ans+b[i].num-1]+=b[i].num;
	for(int i=0;i<n1;++i)printf("%d\n",ans[i]);
	return 0;
}