Submission #874974

#	Time	Username	Problem	Language	Result	Execution time	Memory
874974		makrav	Group Photo (JOI21_ho_t3)	C++14	100 / 100	441 ms	337564 KiB

Main

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef vector<int> vei;
typedef vector<vei> vevei;
 
#define coa               \
            for (auto i : a) {    \
                cout << i << ' '; \
            }                     \
            cout << '\n';
#define cia             \
            for (auto& i : a) { \
                cin >> a;       \
            }
#define cna                       \
            int n;                        \
            cin >> n;                     \
            vector<int> a(n);             \
            for (int i = 0; i < n; i++) { \
                cin >> a[i];              \
            }
#define cnka                      \
            int n, k;                     \
            cin >> n >> k;                \
            vector<int> a(n);             \
            for (int i = 0; i < n; i++) { \
                cin >> a[i];              \
            }
#define cnab                      \
            int n;                        \
            cin >> n;                     \
            vector<int> a(n);             \
            for (int i = 0; i < n; i++) { \
                cin >> a[i];              \
            }                             \
            vector<int> b(n);             \
            for (int i = 0; i < n; i++) { \
                cin >> b[i];              \
            }
#define all(a) (a).begin(), (a).end()
#define sz(a) (int) a.size()
#define con cout << "No\n"
#define coe cout << "Yes\n";
#define str string
#define pb push_back
#define ff first
#define sc second
#define pii pair<ll, ll>
#define mxe max_element
#define mne min_element
#define stf shrink_to_fit
#define f(i, l, r) for (int i = (l); i < (r); i++)
#define double ld
#define int ll
 
int pereh[5001][5001], dp[5001][5001];
 
struct fenwick {
    int n;
    vector<int> t;
    fenwick() = default;
    fenwick(int n_) {
        n = n_;
        t.assign(n + 1, 0);
    }
 
    void clear() {
        t.assign(n + 1, 0);
    }
 
    int sum(int x) {
        int ans = 0;
        for (int i = x; i >= 0; i = (i & (i + 1)) - 1) {
            ans += t[i];
        }
        return ans;
    }
 
    void upd(int pos, int delta) {
        for (int i = pos; i < n; i = i | (i + 1)) {
            t[i] += delta;
        }
    }
};
 
signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
 
    int n; cin >> n;
    vector<int> a(n);
    for (auto& u : a) cin >> u;
    vector<int> pos(n + 1);
    f(i, 0, n)pos[a[i]] = i;
    fenwick fw(n), fw2(n);
    f(i, 1, n + 1)fw.upd(i, 1);
    f(i, 1, n + 1) {
        fw2.clear();
        for (int j = i; j <= n; j++) {
            pereh[i][j] = pereh[i][j - 1] + fw.sum(pos[j]) + fw2.sum(pos[j]) - (j - i);
            //cout << i << ' ' << j << ' ' << pereh[i][j] << '\n';
            fw2.upd(pos[j] + 1, 1);
        }
        fw.upd(pos[i] + 1, -1);
    }
    vector<int> best_dp(n + 1, 1e18);
    best_dp[0] = 0;
    f(i, 1, n + 1) {
        for (int j = 1; j <= i; j++) {
            dp[i][j] = pereh[j][i] + best_dp[j - 1];
            //cout << i << ' ' << j << ' ' << dp[i][j] << '\n';
            best_dp[i] = min(best_dp[i], dp[i][j]);
        }
    }
    cout << best_dp[n] << '\n';
 
    return 0;
}

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