#include "books.h"
#include <string.h>
using namespace std;
const int N = 1000000;
const int SMALL = 1000;
int min(int a, int b) { return a < b ? a : b; }
int max(int a, int b) { return a > b ? a : b; }
typedef vector<int> vi;
int dd[N];
int dp[SMALL][SMALL];
long long minimum_walk(vi pp, int s) {
int n = pp.size(), i, j;
long long ans;
ans = 0;
for (i = 0; i < n; i++)
if (i < pp[i])
ans += pp[i] - i, dd[i]++, dd[pp[i]]--;
else if (i > pp[i])
ans += i - pp[i], dd[pp[i]]++, dd[i]--;
if (s == 0) {
for (i = 1; i < n - 1; i++)
dd[i] += dd[i - 1];
i = n - 1;
while (i >= 0 && pp[i] == i)
i--;
for (i--; i >= 0; i--)
if (dd[i] == 0)
ans += 2;
} else {
int l_, r_, l, r;
for (i = 0; i < n; i++)
memset(dp[i], 0x3f, n * sizeof *dp[i]);
dp[s][s] = 0;
l_ = r_ = pp[s];
for (i = s; i >= 0; i--) {
l_ = min(l_, pp[i]), r_ = max(r_, pp[i]);
l = l_, r = r_;
for (j = s; j < n; j++) {
l = min(l, pp[j]), r = max(r, pp[j]);
if (i > 0)
dp[i - 1][j] = min(dp[i - 1][j], dp[i][j] + (l >= i));
if (j + 1 < n)
dp[i][j + 1] = min(dp[i][j + 1], dp[i][j] + (r <= j));
}
}
ans += dp[0][n - 1] * 2;
}
return ans;
}
