#include "books.h"
#include "bits/stdc++.h"
using namespace std;
using ll = long long;
ll solve(vector<int> p, bool force) {
int n = p.size(), s = 0, t = n-1;
while(!force && p[s]==s) s++;
while(p[t]==t) t--;
ll ans = 0;
vector<int> cnt(n), L(n), R(n);
for(int i=s; i<=t; ++i) {
if(p[i] > i) cnt[i]++, cnt[p[i]]--;
}
int delta = 0;
for(int i=s; i<=t; ++i) {
delta += cnt[i];
L[i] = delta;
}
cnt = vector<int>(n, 0);
for(int i=s; i<=t; ++i) {
if(p[i] < i) {
cnt[i-1]++;
if(p[i]-1>=0) cnt[p[i]-1]--;
}
}
delta = 0;
for(int i=t; i>=s; --i) {
delta += cnt[i];
R[i] = delta;
}
for(int i=s; i<t; ++i) {
ans += max(2, max(L[i], R[i])*2);
}
return ans;
}
ll minimum_walk(vector<int> p, int s) {
int n = p.size();
if(s==0 || p[s]!=s) {
return solve(p, (s==0));
}
ll ans = 1e18+1;
vector<int> q = p;
for(int i=0; i<n; ++i) {
if(i==s) continue;
q[i] = s;
q[s] = p[i];
ans = min(ans, solve(q, 0));
q[i] = p[i];
q[s] = p[s];
}
return ans;
}
