CF 220C Little Elephant and Shifts

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <math.h>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <vector>
#include <string>
#include <iostream>
#include <algorithm>
using namespace std;

#define ll long long
#define ls rt<<1
#define rs ls|1
#define lson l,mid,ls
#define rson mid+1,r,rs
#define middle (l+r)>>1
#define eps (1e-9)
#define type int
#define clr_all(x,c) memset(x,c,sizeof(x))
#define clr(x,c,n) memset(x,c,sizeof(x[0])*(n+1))
#define MOD 1000000007
#define inf 0x3f3f3f3f
#define pi acos(-1.0)

template <class T> void _swap(T &x,T &y){T t=x;x=y;y=t;}
template <class T> T _max(T x,T y){return x>y? x:y;}
template <class T> T _min(T x,T y){return x<y? x:y;}
int test,cas;
const int M=100000 +5;

int n,m;
int ap[M],b[M],cur[M];

struct node{
int id,cur,num;
node(){}
node(int _i,int _c,int _n){id=_i,cur=_c,num=_n;}
bool operator < (const node& t) const{
return num > t.num;
}
};
priority_queue<node>rgt,lft;
int covr,covl;

void run(){
int i,j;
for(i=1;i<=n;i++){
scanf("%d",&j);
ap[j]=i;
}
while(!rgt.empty()) rgt.pop();
while(!lft.empty()) lft.pop();
clr(cur,0,n+1);
for(i=1;i<=n;i++){
scanf("%d",&b[i]);
if(i>ap[b[i]]) rgt.push(node(b[i],0,i-ap[b[i]]));
else lft.push(node(b[i],0,ap[b[i]]-i));
}
covr=covl=0;
node r,l;
for(i=1;;i++){
while(!rgt.empty()){
r=rgt.top();
if(r.cur!=cur[r.id]) rgt.pop();
else if(r.num+covr==0){
rgt.pop();
lft.push(node(r.id,r.cur,-covl));
}else break;
}
while(!lft.empty()){
l=lft.top();
if(l.cur!=cur[l.id]) lft.pop();
else break;
}
int ans=inf;
if(!rgt.empty()) ans=_min(ans,rgt.top().num+covr);
if(!lft.empty()) ans=_min(ans,lft.top().num+covl);
printf("%d\n",ans);
if(i==n) break;
covr--,covl++;
cur[b[i]]++;
if(n>ap[b[i]]) rgt.push(node(b[i],cur[b[i]],n-ap[b[i]]-covr));
else lft.push(node(b[i],cur[b[i]],-covl));
}
}

void preSof(){
}

int main(){
//freopen("input.txt","r",stdin);
//freopen("output.txt","w",stdout);
preSof();
//run();
while(~scanf("%d",&n)) run();
//for(scanf("%d",&test),cas=1;cas<=test;cas++) run();
return 0;
}