Submission #1184000

#	Time	Username	Problem	Language	Result	Execution time	Memory
1184000		jerzyk	Group Photo (JOI21_ho_t3)	C++20	100 / 100	59 ms	568 KiB

Main

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
using namespace __gnu_pbds;
using namespace std;
#define pb push_back
#define st first
#define nd second
typedef long long ll;
typedef long double ld;
const ll I = 1000LL * 1000LL * 1000LL * 1000LL * 1000LL * 1000LL;
const ll M = 1000LL * 1000LL * 1000LL + 7LL;
const int N = 5 * 1000 + 7;
int tab[N], pos[N];
int dp[N];

void Solve()
{
    int n;
    cin >> n;
    for(int i = 1; i <= n; ++i)
    {
        cin >> tab[i];
        pos[tab[i]] = i;
    }
    for(int i = 1; i <= n; ++i)
    {
        int dod = 0; dp[i] = n * n + 100;
        for(int j = i + 1; j <= n; ++j)
            if(pos[j] < pos[i]) ++dod;
        for(int j = i - 1; j >= 0; --j)
        {
            dp[j] += dod;
            dp[i] = min(dp[i], dp[j]);
            if(pos[j] > pos[i]) --dod;
            else ++dod;
        }
    }
    cout << dp[n] << "\n";
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    //int t; cin >> t;
    //while(t--)
        Solve();

    return 0;
}

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