Submission #1369344

#TimeUsernameProblemLanguageResultExecution timeMemory
136934412345678고대 책들 (IOI17_books)C++17
50 / 100
107 ms33556 KiB
#include "books.h"
#include <bits/stdc++.h>

using namespace std;

#define ll long long

const int nx=1e6+5;

int n, vs[nx], qs[nx], offl[nx], offr[nx], mn[nx], mx[nx], cl, cr, L, R;
ll res;

void updaterange()
{
    for (int i=cl; i<=cr; i++)
    {
        if (mn[i]<cl) return cl=mn[i], updaterange();
        if (mx[i]>cr) return cr=mx[i], updaterange();
    }
}

long long minimum_walk(std::vector<int> p, int s) {
    n=p.size();
    for (int i=0; i<n; i++)
    {
        res+=abs(i-p[i]);
        if (vs[i]) continue;
        int cmn=i, cmx=i, u=i;
        vs[i]=1;
        vector<int> pass={u};
        while (p[u]!=i) u=p[u], vs[u]=1, cmx=max(cmx, u), pass.push_back(u);
        qs[cmn]++, qs[cmx]--;
        for (auto u:pass) mn[u]=cmn, mx[u]=cmx;
    }
    for (int i=0; i<n; i++) offl[i]=offr[i]=(mn[i]==mx[i]);
    for (int i=n-2; i>=0; i--) offr[i]=offr[i]&&offr[i+1];
    for (int i=1; i<n; i++) offl[i]=offl[i]&&offl[i-1];
    for (int i=1; i<n; i++) qs[i]+=qs[i-1];
    for (int i=0; i<s; i++) if (qs[i]==0&&!offl[i]) res+=2;
    for (int i=s; i<n-1; i++) if (qs[i]==0&&!offr[i+1]) res+=2;


    L=R=cl=cr=s;
    while (L>0&&qs[L-1]) L--;
    while (R<n-1&&qs[R]) R++;

    while (cl!=L||cr!=R)
    {
        updaterange();
        // cout<<"debug "<<cl<<' '<<cr<<'\n';
        int movel=cl, mover=cr, cstl=0, cstr=0;
        while (movel>L)
        {
            movel--;
            cstl++;
            bool ed=0;
            movel=mn[movel];
            for (int i=mn[movel]; i<=mx[movel]; i++) if (mx[i]>cr) ed=1;
            if (ed) break;
        }
        while (mover<R)
        {
            mover++;
            cstr++;
            bool ed=0;
            mover=mx[mover];
            for (int i=mn[mover]; i<=mx[mover]; i++) if (mn[i]<cl) ed=1;
            if (ed) break;
        }
        // cout<<"here "<<cl<<' '<<cr<<' '<<movel<<' '<<mover<<'\n';
        res+=2*min(cstl, cstr);
        cl=movel, cr=mover;
    }
	return res;
}

/*
7 3
0 5 2 3 4 1 6
*/
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