Submission #1269383

#	Time	Username	Problem	Language	Result	Execution time	Memory
1269383		gay	Group Photo (JOI21_ho_t3)	C++20	44 / 100	5091 ms	476 KiB

Main

#include <bits/stdc++.h>
#include <experimental/random>
#include <random>

using namespace std;
using ll = long long;
using ld = long double;

const ll INF = 1e18, MOD = 998244353;

void solve();

signed main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    ll q = 1;
    //cin >> q;
    while (q--) {
        solve();
    }
}

void solve() {
    ll n;
    cin >> n;
    vector<ll> a(n);
    vector<ll> pos(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        a[i]--;
        pos[a[i]] = i;
    }

    vector<ll> dp(n, INF);
    dp[0] = 0;
    for (int i = 1; i < n; i++) {
        for (int j = i; j >= 0; j--) {
            vector<ll> cur(i + 1);
            iota(cur.begin(), cur.end(), 0);
            reverse(cur.begin() + j, cur.end());
            ll cnt = 0;
            if (j != 0) {
                cnt = dp[j - 1];
            }
            for (int val = j; val <= i; val++) {
                for (int t = 0; t < val; t++) {
                    ll p1 = pos[cur[val]];
                    ll p2 = pos[cur[t]];
                    if (p1 < p2) {
                        cnt++;
                    }
                }
            }
            dp[i] = min(dp[i], cnt);
        }
    }

    cout << dp[n - 1];
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 32 / 32
• Subtask 4: 0 / 20
• Subtask 5: 0 / 36