宠物收养场 Treap

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<queue>
#include<stack>
#include<ctime>
#include<vector>
using namespace std;
int n,m,l=3;
struct node
{
    int key,rev;
    node *child[2];
} bst[20001],*root=NULL,*pos=bst;
queue<node*>mem;
void rotate(node* &r,bool t)
{
    node *y=r->child[!t];
    r->child[!t]=y->child[t];
    y->child[t]=r;
    r=y;
}
void newnode(node* &r,int key)
{
    if(!mem.empty())r=mem.front(),mem.pop();
    else r=pos++;
    r->key=key;
    r->rev=rand();
    r->child[0]=r->child[1]=NULL;
}
void insert(node* &r,int key)
{
    if(!r)newnode(r,key);
    else
    {
        bool t=r->key<key;
        insert(r->child[t],key);
        if(r->rev>r->child[t]->rev)rotate(r,!t);
    }
}
void delet(node* &r,int key)
{
    if(!r)return;
    if(r->key==key)
    {
        if(r->child[1]&&r->child[0])
        {
            bool t=r->child[0]->rev<r->child[1]->rev;
            rotate(r,t);
            delet(r->child[t],key);
        }
        else
        {
            mem.push(r);
            if(r->child[0])r=r->child[0];
            else r=r->child[1];
        }
    }
    else delet(r->child[r->key<key],key);
}
int pre,nxt;
void getspre(node* r,int key)
{
    if(r==NULL)return;
    if(r->key>key)getspre(r->child[0],key);
    else pre=r->key,getspre(r->child[1],key);
}
void getsnext(node* r,int key)
{
    if(r==NULL)return;
    if(r->key<key)getsnext(r->child[1],key);
    else nxt=r->key,getsnext(r->child[0],key);
}
int main()
{
    int i,j,k,ans=0;
    scanf("%d",&n);
    for(i=1; i<=n; i++)
    {
        scanf("%d%d",&j,&k);
        if(j==l||root==NULL)
        {
            insert(root,k);
            l=j;
        }
        else if(j!=l)
        {
            pre=nxt=2000000000;
            getspre(root,k);
            getsnext(root,k);
            if(abs(k-pre)>abs(k-nxt))
            {
                ans+=abs(k-nxt);
                ans%=1000000;
                delet(root,nxt);
            }
            else
            {
                ans+=abs(k-pre);
                ans%=1000000;
                delet(root,pre);
            }
        }
        if(root==NULL)l=3;
    }
    cout<<ans;
    return 0;
}