Submission #801950

#	Time	Username	Problem	Language	Result	Execution time	Memory
801950		Sohsoh84	Giraffes (JOI22_giraffes)	C++17	32 / 100	7067 ms	344 KiB

giraffes

// 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 = 1e6 + 10;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int n, T[MAXN], P[MAXN], F[MAXN], ind[MAXN];

inline void rand_perm() {
	int l = 1, r = n;
	int fl = 1, fr = n;
	for (int i = 1; i <= n; i++) {
		int x = (rng() % 2 ? fr-- : fl++);
		int y = (rng() % 2 ? r-- : l++);
		T[y] = x;
	}
}

inline int distance() {
	for (int i = 1; i <= n; i++)
		ind[P[i]] = i;

	for (int i = 1; i <= n; i++)
		F[ind[T[i]]] = i;

	int ans = 0;
	for (int i = 1; i <= n; i++)
		if (F[i] != i)
			ans++;
	
	return ans;
}
 
int main() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	int fuck = 10000000;
	
	cin >> n;
	for (int i = 1; i <= n; i++) cin >> P[i];

	int ans = n;
	while (fuck--) {
		rand_perm();
		ans = min(ans, distance());
	}

	cout << ans << endl;
	return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 22 / 22
• Subtask 3: 0 / 27
• Subtask 4: 0 / 41