#include "books.h"
#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define mp make_pair
#define pb push_back
typedef long long ll;
typedef pair<int, int> ii;
const int MAX_N = 1e6 + 5;
bitset<MAX_N> visit;
vector<int> p, from;
int n;
ll minimum_walk(vector<int> _p, int s) {
//assert(s == 0);
p = _p;
n = (int)p.size();
from.resize(n);
for (int i = 0; i < n; i++)
from[p[i]] = i;
visit.reset();
vector<ii> temp, segs;
ll ans = 0;
for (int i = 0; i < n; i++) {
if (visit[i]) continue;
int j = i;
int mx = j;
while (!visit[j]) {
mx = max(mx, j);
visit[j] = true;
ans += abs(j - p[j]);
j = p[j];
}
temp.pb(mp(i, mx));
}
segs.pb(temp[0]);
for (auto it : temp) {
if (it.fi < segs.back().se)
segs.back().se = max(segs.back().se, it.se);
else
segs.pb(it);
}
while (segs.size() && segs.back().fi == segs.back().se) segs.pop_back();
int sz = (int)segs.size();
for (int i = 0; i < sz - 1; i++) {
ans += (segs[i + 1].fi - segs[i].se) * 2;
}
return ans;
}
