Submission #1230335

#	Time	Username	Problem	Language	Result	Execution time	Memory
1230335		chikien2009	Group Photo (JOI21_ho_t3)	C++20	100 / 100	401 ms	196396 KiB

Main

#include <bits/stdc++.h>

using namespace std;

void setup()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int n, a[5002], b[5002][5002], c[5002][5002], f[5002], cur;

int main()
{
    setup();

    cin >> n;
    for (int i = 1; i <= n; ++i)
    {
        cin >> a[i];
    }
    for (int i = 1; i <= n; ++i)
    {
        for (int j = 1; j <= n; ++j)
        {
            b[a[i]][a[j]] = (a[i] < a[j]) * (i < j);
            c[a[i]][a[j]] = (a[i] < a[j]) * (i > j);
        }
        for (int j = 1; j <= n; ++j)
        {
            b[a[i]][j] += b[a[i]][j - 1];
        }
        for (int j = n; j >= 1; --j)
        {
            c[a[i]][j] += c[a[i]][j + 1];
        }
    }
    for (int i = 1; i <= n; ++i)
    {
        cur = 0;
        f[i] = 1e9;
        for (int j = i; j >= 1; --j)
        {
            cur += b[j][i] + c[j][i + 1];
            f[i] = min(f[i], f[j - 1] + cur);
        }
    }
    cout << f[n];
    return 0;
}

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