算法导论20（van Emde Boas树）

#include<iostream>
#include<math.h>
using namespace std;

struct node
{
	int u,min,max;
	node *summary;
	node **cluster;
};

void vEBTreeCreate(node *root,int u)
{
	root->u=u;
	root->min=root->max=-1;
	if(u==2)
	{
		root->summary=NULL;
		root->cluster=NULL;
	}
	else
	{
		int v=(int)sqrt((double)u);
		root->summary=new node;
		vEBTreeCreate(root->summary,v);
		root->cluster=new node *[v];
		for(int i=0;i<v;++i)
		{
			root->cluster[i]=new node;
			vEBTreeCreate(root->cluster[i],v);
		}
	}
}

int vEBTreeMinimum(node *root)
{
	return root->min;
}

int vEBTreeMaximum(node *root)
{
	return root->max;
}

int high(int x,int u)
{
	return (int)floor(x/sqrt((double)u));
}

int low(int x,int u)
{
	return x%(int)sqrt((double)u);
}

int index(int x,int y,int u)
{
	return x*(int)sqrt((double)u)+y;
}

bool vEBTreeMember(node *root,int x)
{
	if(x==root->min||x==root->max)return true;
	else if(root->u==2)return false;
	else return vEBTreeMember(root->cluster[high(x,root->u)],low(x,root->u));
}

int vEBTreeSuccessor(node *root,int x)
{
	if(root->u==2)
	{
		if(x==0||root->max==1)return 1;
		else return -1;
	}
	else if(root->min!=-1&&x<root->min)return root->min;
	else
	{
		int maxLow=vEBTreeMaximum(root->cluster[high(x,root->u)]);
		if(maxLow!=-1&&low(x,root->u)<maxLow)
		{
			int offset=vEBTreeSuccessor(root->cluster[high(x,root->u)],low(x,root->u));
			return index(high(x,root->u),offset,root->u);
		}
		else
		{
			int succCluster=vEBTreeSuccessor(root->summary,high(x,root->u));
			if(succCluster==-1)return -1;
			else
			{
				int offset=vEBTreeMinimum(root->cluster[succCluster]);
				return index(succCluster,offset,root->u);
			}
		}
	}
}

int vEBTreePredecessor(node *root,int x)
{
	if(root->u==2)
	{
		if(x==0||root->min==0)return 0;
		else return -1;
	}
	else if(root->max!=-1&&x>root->max)return root->max;
	else
	{
		int minLow=vEBTreeMinimum(root->cluster[high(x,root->u)]);
		if(minLow!=-1&&low(x,root->u)>minLow)
		{
			int offset=vEBTreePredecessor(root->cluster[high(x,root->u)],low(x,root->u));
			return index(high(x,root->u),offset,root->u);
		}
		else
		{
			int predCluster=vEBTreePredecessor(root->summary,high(x,root->u));
			if(predCluster==-1)
			{
				if(root->min!=-1&&x>root->min)return root->min;
				else return -1;
			}
			else
			{
				int offset=vEBTreeMaximum(root->cluster[predCluster]);
				return index(predCluster,offset,root->u);
			}
		}
	}
}

void vEBEmptyTreeInsert(node *root,int x)
{
	root->min=root->max=x;
}

void vEBTreeInsert(node *root,int x)
{
	if(root->min==-1)vEBEmptyTreeInsert(root,x);
	else
	{
		if(x<root->min)
		{
			int tmp=x;
			x=root->min;
			root->min=tmp;
		}
		if(root->u>2)
		{
			if(vEBTreeMinimum(root->cluster[high(x,root->u)]))
			{
				vEBTreeInsert(root->summary,high(x,root->u));
				vEBEmptyTreeInsert(root->cluster[high(x,root->u)],low(x,root->u));
			}
			else vEBTreeInsert(root->cluster[high(x,root->u)],low(x,root->u));
		}
		if(x>root->max)root->max=x;
	}
}

void vEBTreeDelete(node *root,int x)
{
	if(root->min==root->max)root->min=root->max=-1;
	else if(root->u==2)
	{
		if(x==0)root->min=1;
		else root->min=0;
		root->max=root->min;
	}
	else if(x==root->min)
	{
		int firstCluster=vEBTreeMinimum(root->summary);
		x=index(firstCluster,vEBTreeMinimum(root->cluster[firstCluster]),root->u);
		root->min=x;
		vEBTreeDelete(root->cluster[high(x,root->u)],low(x,root->u));
		if(vEBTreeMinimum(root->cluster[high(x,root->u)])==-1)
		{
			vEBTreeDelete(root->summary,high(x,root->u));
			if(x==root->max)
			{
				int summaryMax=vEBTreeMaximum(root->summary);
				if(summaryMax==-1)root->max=root->min;
				else root->max=index(summaryMax,vEBTreeMaximum(root->cluster[summaryMax]),root->u);
			}
		}
		else if(x==root->max)root->max=index(high(x,root->u),vEBTreeMaximum(root->cluster[high(x,root->u)]),root->u);
	}
}

int main()
{
	node *root=new node;
	vEBTreeCreate(root,16);
	vEBTreeInsert(root, 1);
	vEBTreeDelete(root, 1);
	return 0;
}