CDQ分治

标签：turn   void   ret   end   ++   owb   int   clu   lan   

#include<bits/stdc++.h>
using namespace std;
const int maxn=200005;
struct node{
	int a;
	int b;
	int c;
	int cnt;
	int ans;
}s1[maxn],s2[maxn];
int n,m,k,mx,top,su[maxn];
int c[maxn];
bool cmp1(node x,node y)
{
	if(x.a==y.a)
	{
		if(x.b==y.b)
		return x.c<y.c;
		else return x.b<y.b;
	}
	else  return x.a<y.a;
}
bool cmp2(node x,node y)
{
	if(x.b==y.b)
	return x.c<y.c;
	else return x.b<y.b;
}
int lowbit(int x)
{
	return x&(-x);
}
void add(int x,int y)
{
	while(x<=mx)
	{
		c[x]=c[x]+y;
		x+=lowbit(x);
	}
	
}
int query(int x)
{
	int sum=0;
	while(x)
	{
		sum+=c[x];
		x-=lowbit(x);
	}
	return sum;
}
void cdq(int l,int r)
{
	if(l==r)
	return ;
	int mid=(l+r)>>1;
	cdq(l,mid);
	cdq(mid+1,r);
	sort(s2+l,s2+mid+1,cmp2);
	sort(s2+1+mid,s2+r+1,cmp2);
	int i,j=l;
	for(int i=mid+1;i<=r;i++)
	{
		while(s2[i].b>=s2[j].b&&j<=mid)
		{
			add(s2[j].c,s2[j].cnt);
			j++;
		}
		s2[i].ans+=query(s2[i].c);
	}
	for(i=l;i<j;++i)
	add(s2[i].c,-s2[i].cnt); 
}
int main()
{
	cin>>n>>k;
	mx=k;
	for(int i=1;i<=n;i++)
	{
		
		int a,b,c;
		cin>>a>>b>>c;
		s1[i].a=a;
	    s1[i].b=b;
	    s1[i].c=c;
	}
	sort(s1+1,s1+1+n,cmp1);
	for(int i=1;i<=n;i++)
	{
		top++;
		if(s1[i].a!=s1[i+1].a||s1[i].b!=s1[i+1].b||s1[i].c!=s1[i+1].c)
		{
			m++;
			s2[m].a=s1[i].a;
			s2[m].b=s1[i].b;
			s2[m].c=s1[i].c;
			s2[m].cnt=top;
			top=0;
		}
	}
	cdq(1,m);
	for(int i=1;i<=m;i++)
	su[s2[i].ans+s2[i].cnt-1]+=s2[i].cnt;
	for(int i=0;i<n;i++)
	cout<<su[i]<<endl;
	return 0;
 } 

CDQ分治

标签：turn   void   ret   end   ++   owb   int   clu   lan   

原文地址：https://www.cnblogs.com/bangdexuanyuan/p/13424513.html