splay

来源:互联网 发布:ios程序员工资待遇知乎 编辑:程序博客网 时间:2024/03/29 10:15
#include<iostream>#include<cstdio>#define inf 1000000000using namespace std;int ans,n,t1,t2,rt,size;int tr[50001][2],fa[50001],num[50001];void rotate(int x,int &k){    int y=fa[x],z=fa[y],l,r;    if(tr[y][0]==x)l=0;else l=1;r=l^1;    if(y==k)k=x;    else{if(tr[z][0]==y)tr[z][0]=x;else tr[z][1]=x;}    fa[x]=z;fa[y]=x;fa[tr[x][r]]=y;    tr[y][l]=tr[x][r];tr[x][r]=y; }void splay(int x,int &k){int y,z;while(x!=k){y=fa[x],z=fa[y];if(y!=k){if((tr[y][0]==x)^(tr[z][0]==y))rotate(x,k);else rotate(y,k);}rotate(x,k);}}void ins(int &k,int x,int last){     if(k==0){size++;k=size;num[k]=x;fa[k]=last;splay(k,rt);return;}     if(x<num[k])ins(tr[k][0],x,k); else ins(tr[k][1],x,k); }void ask_before(int k,int x){     if(k==0)return;     if(num[k]<=x){t1=num[k];ask_before(tr[k][1],x);}     else ask_before(tr[k][0],x); }void ask_after(int k,int x){   if(k==0)return;   if(num[k]>=x){t2=num[k];ask_after(tr[k][0],x);}   else ask_after(tr[k][1],x);}int main(){scanf("%d",&n);for(int i=1;i<=n;i++){        int x;if(scanf("%d",&x)==EOF)x=0;        t1=-inf;t2=inf;    ask_before(rt,x);    ask_after(rt,x);    if(i!=1)ans+=min(x-t1,t2-x);    else ans+=x;    ins(rt,x,0);}printf("%d",ans);return 0;}

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