Submission #995195

#	Time	Username	Problem	Language	Result	Execution time	Memory
995195		gmroh06	Group Photo (JOI21_ho_t3)	C++14	100 / 100	159 ms	199776 KiB

Main

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

inline void fastio() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    std::cout.tie(nullptr);
}

ll n, arr[5050], p[5050], dp[5050], sum[5050][5050];

int main() {
    fastio();

    cin >> n;

    for (ll i = 1; i <= n; i++) {
        cin >> arr[i];
        p[arr[i]] = i;
    }

    for (ll i = 1; i <= n; i++) {
        for (ll j = 1; j <= n; j++) {
            sum[i][j] += sum[i - 1][j] + (arr[i] <= j);
        }
    }

    memset(dp, 0x3f, sizeof(dp));

    *dp = 0;

    for (ll i = 1; i <= n; i++) {
        for (ll j = i, tmp = 0; j > 0; j--) {
            tmp += (i - j) + (sum[p[j]][n] - sum[p[j]][i]) - (sum[p[j]][i] - sum[p[j]][j]);
            dp[i] = min(dp[i], dp[j - 1] + tmp);
        }
    }

    cout << dp[n];

    return 0;
}

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