제출 #593151

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
593151		piOOE	Group Photo (JOI21_ho_t3)	C++17	100 / 100	157 ms	196480 KiB

Main

#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    vector<int> a(n), reva(n);
    vector<vector<int>> pl(n, vector<int>(n));
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
        --a[i];
        reva[a[i]] = i;
    }
    for (int i = 0; i < n; ++i) {
        pl[i][i] = 1;
        for (int j = i + 1; j < n; ++j) {
            pl[i][j] = pl[i][j - 1] + (reva[j] < reva[i]);
        }
    }
    vector<vector<int>> dp(n, vector<int>(n + 1, 1000'000'000));
    dp[n - 1][1] = 0;
    for (int x = n - 2; x >= 0; --x) {
        for (int cnt = 1; cnt + 1 + x <= n; ++cnt) {
            dp[x][1] = min(dp[x][1], dp[x + 1][cnt] + abs(pl[x][n - 1] - 1));
        }
        for (int cnt = 2; x + cnt <= n; ++cnt) {
            dp[x][cnt] = dp[x + 1][cnt - 1] + (pl[x][n - 1] - pl[x][x + cnt - 1]) + abs(pl[x][x + cnt - 1] - cnt);
        }
    }
    int ans = n * n;
    for (int i = 1; i <= n; ++i) {
        ans = min(ans, dp[0][i]);
    }
    cout << ans;
    return 0;
}

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