#include <bits/stdc++.h>
#include "books.h"
#define sz(x) ((int)x.size())
#define all(x) x.begin(),x.end()
#define PB push_back
using namespace std;
typedef long long ll;
const int N = 1010;
const ll OO = 1e18;
vector<array<int, 2> > vc;
queue<int> q;
vector<ll> f[N];
ll ans = 0, mn = ll(1e9);
int n, lf, rt, le[N], ri[N];
long long minimum_walk(std::vector<int> p, int s) {
n = sz(p);
if (n > 1000){
vc.clear();
for (int i = 0; i < n; i++){
ans += abs(p[i] - i);
if (p[i] != i)
vc.PB({min(p[i], i), max(p[i], i)});
}
if (sz(vc)) {
sort(all(vc));
int lst = 0;
for (array<int, 2> cr : vc)
if (cr[0] > lst){
ans += 2 * (cr[0] - lst);
lst = cr[1];
} else lst = max(lst, cr[1]);
}
return ans;
}
bool was = 0;
for (int i = 0; i < n; i++){
ans += abs(p[i] - i);
if (p[i] != i) {
was = 1;
lf = min(lf, i);
rt = max(rt, i);
}
}
if (!was) return 0;
for (int i = 0; i < n; i++){
le[i] = ri[i] = i;
q.push(i);
while (sz(q)){
int v = q.front(); q.pop();
int nl = v, nr = p[v];
if (nl > nr) swap(nl, nr);
if (nl < le[i]){
for (int j = nl; j < le[i]; j++)
q.push(j);
le[i] = nl;
}
if (nr > ri[i]){
for (int j = ri[i] + 1; j <= nr; j++)
q.push(j);
ri[i] = nr;
}
}
}
for (int i = lf; i <= s; i++){
f[i].resize(n);
fill(all(f[i]), OO);
}
f[le[s]][ri[s]] = 0;
int len = rt - lf + 1;
for (int k = 1; k < len; k++)
for (int l = lf; l <= s && l + k - 1 <= rt; l++){
int r = l + k - 1;
if (f[l][r] == OO) continue;
if (l > lf){
int nl = min(l - 1, le[l - 1]);
int nr = max(r, ri[l - 1]);
f[nl][nr] = min(f[nl][nr], f[l][r] + 2);
}
if (r < rt){
int nl = min(l, le[r + 1]);
int nr = max(r + 1, ri[r + 1]);
f[nl][nr] = min(f[nl][nr], f[l][r] + 2);
}
}
return ans + f[lf][rt];
}
