splay 1296 营业额统计

有一个点超时，确实是个很简单的splay
#include<cstdio>
#include<iostream>
using namespace std;
int n,shu[1000006][2],root,size,b1,b2,sum1,sum[1000005],zhi[1000005];
int fa[1000005];
void xuan(int a1)
{
	int a2,a3,l,r;
	a2=fa[a1];
	a3=fa[a2];
	if(a2==root)
	  root=a1;
	else
	  if(a2==shu[a3][0])
	    shu[a3][0]=a1;
	  else
	    shu[a3][1]=a1;
	if(shu[a2][0]==a1)
	  l=0;
	else
	  l=1;
	r=l^1;
	fa[a1]=a3;
	fa[a2]=a1;
	shu[a2][l]=shu[a1][r];
	shu[a1][r]=a2;
	fa[shu[a2][l]]=a2;
	return;
}
void zhuan(int a1)
{
	int a2,a3;
	for(;a1!=root;)
	  {
	  	a2=fa[a1];
	  	a3=fa[a2];
	  	if(a2!=root)
	  	  if(a2==shu[a3][0]^a1==shu[a2][0])
	  	    xuan(a1);
	  	  else
	  	    xuan(a2);
	  	xuan(a1);
	  }
}
void jia(int &a1,int a2,int a3)
{
	if(a1==0)
	  {
	  	size++;
	  	a1=size;
	  	zhi[a1]=a2;
	  	sum[a1]=1;
	  	fa[a1]=a3;
	  	zhuan(a1);
	  	return;
	  }
	if(zhi[a1]==a2)
	  sum[a1]++;
	else
	  if(zhi[a1]<a2)
	    jia(shu[a1][1],a2,a1);
	  else
	    jia(shu[a1][0],a2,a1);
	return;
}
void qian(int a1,int a2)
{
	if(a1==0)
	  return;
	if(zhi[a1]==a2)
	  b1=a2;
	else
	  if(zhi[a1]<a2)
	    {
	    	b1=zhi[a1];
	    	qian(shu[a1][1],a2);
		}
	  else
	    qian(shu[a1][0],a2);
	return;
}
void hou(int a1,int a2)
{
	if(a1==0)
	  return;
	if(zhi[a1]==a2)
	  b2=a2;
	else
	  if(zhi[a1]>a2)
	    {
	    	b2=zhi[a1];
	    	hou(shu[a1][0],a2);
		}
	  else
	    hou(shu[a1][1],a2);
	return;
}
int main()
{
	scanf("%d",&n);
	scanf("%d",&sum1);
	jia(root,sum1,0);
	for(int i=1;i<n;i++)
	  {
	  	int a1;
	  	scanf("%d",&a1);
	  	b1=-1;
	  	b2=-1;
	  	qian(root,a1);
	  	hou(root,a1);
	  	if(b1==-1)
	  	  sum1+=b2-a1;
	  	else
	  	  if(b2==-1)
	  	    sum1+=a1-b1;
	  	  else
	  	    if(a1-b1<=b2-a1)
	  	      sum1+=a1-b1;
	  	    else
	  	      sum1+=b2-a1;
	  	jia(root,a1,0);
	  }
	printf("%d",sum1);
	return 0;
}