bzoj 1588 营业额统计 splay

题意：给出一个n个数的数列a,对于第i个元素ai定义fi=min(abs(ai-aj))，(1<=j<i)，其中f1=a1。输出sum(fi) (1<=i<=n)

// File Name: 1588.cpp
// Author: Zlbing
// Created Time: 2013年08月09日 星期五 12时21分58秒

#include<iostream>
#include<string>
#include<algorithm>
#include<cstdlib>
#include<cstdio>
#include<set>
#include<map>
#include<vector>
#include<cstring>
#include<stack>
#include<cmath>
#include<queue>
using namespace std;
#define CL(x,v); memset(x,v,sizeof(x));
#define INF 0x3f3f3f3f
#define LL long long
#define REP(i,r,n) for(int i=r;i<=n;i++)
#define RREP(i,n,r) for(int i=n;i>=r;i--)
const int MAXN=200010;
const int mod=1000000;

struct SplayTree {  
    int sz[MAXN];  
    int ch[MAXN][2];  
    int pre[MAXN];  
    int rt,top;  
    inline void up(int x){  
        sz[x]  = cnt[x]  + sz[ ch[x][0] ] + sz[ ch[x][1] ];  
    }  
    inline void Rotate(int x,int f){  
        int y=pre[x];  
        ch[y][!f] = ch[x][f];  
        pre[ ch[x][f] ] = y;  
        pre[x] = pre[y];  
        if(pre[x]) ch[ pre[y] ][ ch[pre[y]][1] == y ] =x;  
        ch[x][f] = y;  
        pre[y] = x;  
        up(y);  
    }  
    inline void Splay(int x,int goal){//将x旋转到goal的下面  
        while(pre[x] != goal){  
            if(pre[pre[x]] == goal) Rotate(x , ch[pre[x]][0] == x);  
            else   {  
                int y=pre[x],z=pre[y];  
                int f = (ch[z][0]==y);  
                if(ch[y][f] == x) Rotate(x,!f),Rotate(x,f);  
                else Rotate(y,f),Rotate(x,f);  
            }  
        }  
        up(x);  
        if(goal==0) rt=x;  
    }  
    inline void RTO(int k,int goal){//将第k位数旋转到goal的下面  
        int x=rt;  
        while(sz[ ch[x][0] ] != k-1) {  
            if(k < sz[ ch[x][0] ]+1) x=ch[x][0];  
            else {  
                k-=(sz[ ch[x][0] ]+1);  
                x = ch[x][1];  
            }  
        }  
        Splay(x,goal);  
    }  
    inline void vist(int x){  
        if(x){  
            printf("结点%2d : 左儿子  %2d   右儿子  %2d   %2d sz=%d\n",x,ch[x][0],ch[x][1],val[x],sz[x]);  
            vist(ch[x][0]);  
            vist(ch[x][1]);  
        }  
    }  
    inline void Newnode(int &x,int c){  
        x=++top;  
        ch[x][0] = ch[x][1] = pre[x] = 0;  
        sz[x]=1; cnt[x]=1;  
        val[x] = c;  
    }  
    inline void init(){  
        ch[0][0]=ch[0][1]=pre[0]=sz[0]=0;  
        rt=top=0; cnt[0]=0;  
        Newnode(rt,-INF);  
        Newnode(ch[rt][1],INF);  
        pre[top]=rt;  
        sz[rt]=2;  
    }  
    inline void Insert(int &x,int key,int f){  
        if(!x) {  
            Newnode(x,key);  
            pre[x]=f;  
            Splay(x,0);//效率的保证  
            return ;  
        }  
        if(key==val[x]){  
            cnt[x]++;  
            sz[x]++;  
            Splay(x,0);//不加会超时，囧啊  
            return ;  
        }else if(key<val[x]) {  
            Insert(ch[x][0],key,x);  
        } else {  
            Insert(ch[x][1],key,x);  
        }  
        up(x);  
    }  
    void findpre(int x,int key,int &ans){  
        if(!x)  return ;  
        if(val[x] <= key){  
            ans=val[x];  
            findpre(ch[x][1],key,ans);  
        } else  
            findpre(ch[x][0],key,ans);  
    }  
    void findsucc(int x,int key,int &ans){  
        if(!x) return ;  
        if(val[x]>=key) {  
            ans=val[x];  
            findsucc(ch[x][0],key,ans);  
        } else  
            findsucc(ch[x][1],key,ans);  
    }  
    int cnt[MAXN];  
    int val[MAXN];  

}spt;  
int main()
{
    int n;
    scanf("%d",&n);
    spt.init();
    int ans=0;
    int a;
    scanf("%d",&a);
    spt.Insert(spt.rt,a,0);
    ans=a;
    n--;
    while(n--)
    {
        a=0;//不知道为什么这里要赋值为0，不赋值就wa!!
        scanf("%d",&a);
        int x,y;
        spt.findpre(spt.rt,a,x);
        spt.findsucc(spt.rt,a,y);
        if(abs(a-x)<=abs(a-y))
        {
            ans+=abs(a-x);
        }
        else
        {
            ans+=abs(a-y);
        }
        spt.Insert(spt.rt,a,0);
    }
    printf("%d\n",ans);
    return 0;
}