// Wounds should become scars but I'm cracked instead U+1FAE0
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define all(x) (x).begin(),(x).end()
#define X first
#define Y second
#define sep ' '
#define endl '\n'
#define debug(x) cerr << #x << ": " << x << endl;
const ll MAXN = 500 + 10;
const ll TMAX = 1e6 + 10;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int dp[MAXN][MAXN][MAXN], n, P[TMAX];
inline int rand_perm() {
int l = 1, r = n;
int fl = 1, fr = n;
int ans = n;
for (int i = 1; i <= n; i++) {
if (P[l] == fl) {
ans--;
l++;
fl++;
} else if (P[l] == fr) {
ans--;
l++;
fr--;
} else if (P[r] == fl) {
ans--;
r--;
fl++;
} else if (P[r] == fr) {
ans--;
r--;
fr--;
} else {
int tfl = fl;
int tfr = fr;
if (ind[fl] < l || ind[fl] > r) tfl++;
else if (ind[fr] < l || ind[fr] > r) tfr--;
else if (rng() % 2) tfl++;
else tfr--;
if (P[l] < fl || P[l] > fr) l++;
else if (P[r] < fl || P[r] > fr) r--;
else if (rng() % 2) l++;
else r--;
fl = tfl;
fr = tfr;
}
}
return ans;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin >> n;
for (int i = 1; i <= n; i++) cin >> P[i];
if (n < MAXN) {
for (int len = 1; len <= n; len++) {
for (int l = 1; l <= n - len + 1; l++) {
for (int tl = 1; tl <= n - len + 1; tl++) {
int r = l + len - 1;
int tr = tl + len - 1;
if (P[l] == tl) dp[len][l][tl] = dp[len - 1][l + 1][tl + 1] + 1;
else if (P[r] == tl) dp[len][l][tl] = dp[len - 1][l][tl + 1] + 1;
else if (P[l] == tr) dp[len][l][tl] = dp[len - 1][l + 1][tl] + 1;
else if (P[r] == tr) dp[len][l][tl] = dp[len - 1][l][tl] + 1;
else dp[len][l][tl] = max({
dp[len - 1][l][tl],
dp[len - 1][l + 1][tl],
dp[len - 1][l][tl + 1],
dp[len - 1][l + 1][tl + 1]
});
}
}
}
cout << n - dp[n][1][1] << endl;
} else {
int fuck = 10000000 * 13 / n;
int ans = n;
while (fuck--) {
ans = min(ans, rand_perm());
}
cout << ans << endl;
}
return 0;
}
Compilation message
giraffes.cpp: In function 'int rand_perm()':
giraffes.cpp:49:8: error: 'ind' was not declared in this scope; did you mean 'int'?
49 | if (ind[fl] < l || ind[fl] > r) tfl++;
| ^~~
| int
