[bzoj] 1588 营业额统计 || Splay板子题

原题

给出一个n个数的数列ai ,对于第i个元素ai定义\(fi=min(|ai-aj|) (1<=j<i)\)，f1=a1,求\(/sumfi\)

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Splay板子题。

Splay讲解：http://www.cnblogs.com/mrsheep/p/8110483.html

//太懒了……

#include<cstdio>
#include<algorithm>
#include<cmath>
#define which(x) (ls[f[(x)]]==(x))
#define N 33000
using namespace std;
int n,v,root,ls[N],rs[N],val[N],f[N],idx,ans;

void Rotate(int u)
{
    int v=f[u],w=f[v],b=which(u)?rs[u]:ls[u],dir=which(v);
    which(u)?(rs[u]=v,ls[v]=b):(ls[u]=v,rs[v]=b);
    f[v]=u;f[b]=v;f[u]=w;
    if (w) dir?ls[w]=u:rs[w]=u;
}

int read()
{
    int ans=0,fu=1;
    char j=getchar();
    for (;j<'0' || j>'9';j=getchar()) if (j=='-') fu=-1;
    for (;j>='0' && j<='9';j=getchar()) ans*=10,ans+=j-'0';
    return ans*fu;
}

void splay(int x,int y)
{
    while (f[x]!=y)
    {
    if (f[f[x]]!=y)
    {
        if (which(x)==which(f[x])) Rotate(f[x]);
        else Rotate(x);
    }
    Rotate(x);
    }
    if (!y) root=x;
}

void insert(int x)
{
    int u=root,v=0;
    while (u)
    {
    v=u;
    if (x<val[u]) u=ls[u];
    else u=rs[u];
    }
    f[++idx]=v;
    val[idx]=x;
    if (v) x<val[v]?ls[v]=idx:rs[v]=idx;
    splay(idx,0);
}

int getmx(int x)
{
    if (!x) return 97797977;
    while (rs[x]) x=rs[x];
    return val[x];
}

int getmn(int x)
{
    if (!x) return 97797977;
    while (ls[x]) x=ls[x];
    return val[x];
}

int query()
{
    int lmx=getmx(ls[root]),rmn=getmn(rs[root]);
    return min(abs(val[root]-lmx),abs(val[root]-rmn));
}

int main()
{
    n=read();
    v=read();
    insert(v);
    ans+=v;
    for (int i=2;i<=n;i++)
    {
    v=read();
    insert(v);
    ans+=query();
    }
    printf("%d",ans);
    return 0;
}