#include <bits/stdc++.h>
#include "books.h"
using namespace std;
long long minimum_walk(std::vector<int> p, int s) {
#define int long long
int l = 0, r = p.size()-1;
int maxi = -1;
int ans = -2;
int n = p.size();
for(int i = 0; i < (int)p.size(); i++){
l = i;
if(p[i] != i){
break;
}
}
for(int i = (int)p.size()-1; i >= 0; i--){
r = i;
if(p[i] != i){
break;
}
}
if(l >= r) return 0;
if(s == 0){
for(int i = l; i <= r; i++){
ans += abs(p[i]-i);
maxi = max(maxi, (int)p[i]);
if(i >= maxi){
ans += 2;
}
}
return ans + 2*l;
}
vector< bool > visited(n, false);
ans = 0;
for(int i = 0; i < n; i++){
ans += abs(i-p[i]);
for(int j = i; j < p[i]; j++){
visited[j] = true;
}
}
for(int i = min(l,(int)s); i <= max((int)s,r); i++){
ans += (!visited[i])*2;
}
return ans;
#undef int
}
