Submission #637587

#	Time	Username	Problem	Language	Result	Execution time	Memory
637587		danikoynov	Group Photo (JOI21_ho_t3)	C++14	64 / 100	5037 ms	360 KiB

Main

/**
 ____ ____ ____ ____ ____ ____
||l |||e |||i |||n |||a |||d ||
||__|||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|/__\|

**/

#include<bits/stdc++.h>
#define endl '\n'

using namespace std;
typedef long long ll;

void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

const int maxn = 5010;

int n, a[maxn], dp[maxn], pos[maxn], fen[maxn];
void add(int pos, int val)
{
    for (int i = pos; i <= n; i += (i & -i))
        fen[i] += val;
}

int query(int pos)
{
    int s = 0;
    for (int i = pos; i > 0; i -= (i & -i))
        s += fen[i];
    return s;
}

void solve()
{
    cin >> n;
    for (int i = 1; i <= n; i ++)
    {
        cin >> a[i];
        pos[a[i]] = i;
    }

    for (int i = 1; i <= n; i ++)
    {
        dp[i] = n * n;
        for (int j = 0; j < i; j ++)
        {

            if (j > 0)
                add(pos[j], 1);
            int st = j + 1, sum = 0;
            for (int k = i; k > j; k --)
            {
                ll cur = pos[k] + (j + (i - k) - query(pos[k] - 1));
                ///cout << i << " " << j << " " << k << " " << cur << endl;
                add(pos[k], 1);
                cur -= st;
                st ++;
                sum = sum + max((ll)0, cur);
            }

            for (int k = i; k > j; k --)
                add(pos[k], - 1);
            ///cout << i << " " << j << " " << sum << endl;
            dp[i] = min(dp[i], dp[j] + sum);
        }

        for (int j = 0; j < i; j ++)
            if (j > 0)
                add(pos[j], - 1);
        ///cout << i << " -- " << dp[i] << endl;

    }
    cout << dp[n] << endl;

}

int main()
{
    solve();
    return 0;
}

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