Submission #1278780

#	Time	Username	Problem	Language	Result	Execution time	Memory
1278780		MMihalev	Ancient Books (IOI17_books)	C++20	50 / 100	98 ms	28000 KiB

books

#include<iostream>
#include<vector>
//#include "books.h"
using namespace std;
const int MAX_N=1e6+6;
int col[MAX_N];
int cols;
int a[MAX_N];
int l[MAX_N];
int r[MAX_N];
int n;
long long ans;
long long minimum_walk(std::vector<int> p, int s)
{
    n=p.size();
    s++;
    for(int i=1;i<=n;i++)
    {
        l[i]=1e9;
        r[i]=-1;
        a[i]=p[i-1]+1;
    }
    ///init stuff

    for(int i=1;i<=n;i++)
    {
        ans+=abs(i-a[i]);
        if(col[i]==0)
        {
            if(i!=s && i==a[i])continue;
            cols++;
            int pos=i;
            while(col[pos]==0)
            {
                l[cols]=min(l[cols],pos);
                r[cols]=max(r[cols],pos);
                col[pos]=cols;
                pos=a[pos];
            }
        }
    }

    int tmpstart=-1,tmpend=-1;
    int compstart=-1,compend=-1;

    vector<int>sep;
    bool has=0;
    int active=0;
    int e=n;
    while(col[e]==0)e--;
    for(int i=1;i<=e;i++)
    {
        if(has && active==0)
        {
            sep.push_back(i-1);
        }

        int curcol=col[i];
        if(l[curcol]==i)
        {
            if(active==0)tmpstart=i;
            has=1;
            active++;
        }
        if(r[curcol]==i)
        {
            if(active==1)
            {
                tmpend=i;
            }
            active--;
        }

        if(tmpstart<=s && s<=tmpend)
        {
            compstart=tmpstart;
            compend=tmpend;
        }
    }


    int ll=s,rr=s;
    int oldl=ll+1,oldr=rr-1;

    while(s>1)
    {
        if(ll==compstart && rr==compend)break;

        int nl=ll,nr=rr;

        for(int i=ll;i<oldl;i++)
        {
            if(!col[i])continue;
            nl=min(nl,l[col[i]]);
            nr=max(nr,r[col[i]]);
        }
        for(int i=oldr+1;i<=rr;i++)
        {
            if(!col[i])continue;
            nl=min(nl,l[col[i]]);
            nr=max(nr,r[col[i]]);
        }

        if(nl!=ll or nr!=rr)
        {
            oldl=ll;
            oldr=rr;
            ll=nl;
            rr=nr;
        }
        else
        {
            int tmpl=ll-1,tmpr=rr+1;
            ans++;
            while(col[tmpl]==0 && col[tmpr]==0)
            {
                ans++;
                tmpl--;
                tmpr++;
            }
            break;

            if(col[tmpl]!=0)
            {
                ll=l[col[tmpl]];
                rr=r[col[tmpl]];
            }
            else
            {
                ll=l[col[tmpr]];
                rr=r[col[tmpr]];
            }

            //while(col[tmpl]==0)tmpl--;
            //while(col[tmpr]==0)tmpr++;

            oldl=tmpl;
            oldr=tmpr;
        }
    }



    if(sep.size()==0)return ans;
    ///cycle stuff


    for(int i=sep.size()-1;i>=0;i--)
    {
        if(sep[i]>=s)ans+=2;
    }
    ///right part


    for(int i=0;i<sep.size();i++)
    {
        if(sep[i]<s)ans+=2;
    }
    ///left part


	return ans;
}

• Subtask 1: 12 / 12
• Subtask 2: 10 / 10
• Subtask 3: 28 / 28
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30