#include <bits/stdc++.h>
#include "books.h"
using namespace std;
typedef long long ll;
const int MAXN = 1e6 + 50;
int L[MAXN], R[MAXN], vis1[MAXN], vis2[MAXN];
int ind[MAXN];
void ext(int& l, int& r) {
int mL = min(l, min(L[ind[l]], L[ind[r]]));
int mR = max(r, max(R[ind[l]], R[ind[r]]));
while (mL < l || r < mR) {
if (mL < l) {
l--;
mL = min(mL, L[ind[l]]);
mR = max(mR, R[ind[l]]);
} else {
r++;
mL = min(mL, L[ind[r]]);
mR = max(mR, R[ind[r]]);
}
}
}
ll minimum_walk(vector<int> p, int s) {
int n = p.size();
if (s != 0) {
ll ret = 0;
int l = s, r = s, c = 0;
for (int i = 0; i < n; i++) ind[i] = -1;
for (int i = 0; i < n; i++) {
ret += (ll) abs(p[i] - i);
if (ind[i] != -1) continue;
int j = i;
L[c] = i, R[c] = i;
do {
ind[j] = c;
// L[c] = min(L[c], j);
R[c] = max(R[c], j);
j = p[j];
} while(i != j);
if (i != p[i])
l = min(l, L[c]), r = max(r, R[c]);
c++;
}
int curL = s, curR = s;
do {
ext(curL, curR);
int c1 = 0, c2 = 0;
int mL1 = curL, mR1 = curR;
int f1 = 0, f2 = 0;
while (l < mL1) {
mL1--;
c1 += 2;
ext(mL1, mR1);
if (mR1 > curR) {
f1 = true;
break;
}
}
int mL2 = curL, mR2 = curR;
while (mR2 < r) {
mR2++;
c2 += 2;
ext(mL2, mR2);
if (mL2 < curL) {
f2 = true;
break;
}
}
if (f1 && f2)
ret += min(c1, c2);
else
ret += c1 + c2;
curL = min(mL1, mL2);
curR = max(mR1, mR2);
} while (l < curL || curR < r);
return ret;
}
ll ret = 0;
ll sum = 0;
vis1[0] = 1;
vis2[n] = 0;
for (int i = 1; i < n; i++)
vis1[i] = vis1[i-1] | (p[i] != i);
for (int i = n - 1; i > 0; i--)
vis2[i] = vis2[i + 1] | (p[i] != i);
for (int i = 0; i < n; i++) {
ret += (ll) abs(p[i] - i);
sum += (ll) p[i];
if (sum * 2 == 1ll * (ll) i * (1ll * (ll) i + 1) && i != n - 1 && vis1[i] && vis2[i + 1])
ret += 2;
}
return ret;
}
