Submission #499809

#	Time	Username	Problem	Language	Result	Execution time	Memory
499809		Lobo	Group Photo (JOI21_ho_t3)	C++17	44 / 100	34 ms	444 KiB

Main

#include<bits/stdc++.h>
using namespace std;

/*for ordered_set
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<pair<int,int>, null_type,less<pair<int,int>>, rb_tree_tag,tree_order_statistics_node_update>
*/

const long long INFll = (long long) 1e18 + 10;
const int INFii = (int) 1e9 + 10;
typedef long long ll;
typedef int ii;
typedef long double dbl;
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()

#define maxn 220

ii n, a[maxn], pos[maxn], bit[maxn], dp[maxn], mark[maxn];

void att(ii id, ii val) {
    for(ii i = id; i <= n; i+= i&-i) {
        bit[i]+= val;
    }
}

ii qr(ii id) {
    ii val = 0;
    for(ii i = id; i > 0; i-= i&-i) {
        val+= bit[i];
    }
    return val;
}

ii sol(ii i) {
    if(mark[i]) return dp[i];
    mark[i] = 1;
    ii ans = INFii;
    if(i == n) return dp[i] = 0;

    for(ii k = i+1; k <= n; k++) {
        ii ans1 = 0;

        for(ii j = 1; j <= n; j++) {
            bit[j] = 0;
        }

        for(ii j = 1; j <= i; j++) {
            att(pos[j],1);
        }

        for(ii j = k; j >= i+1; j--) {
            ans1+= j-1-qr(pos[j]);
            att(pos[j],+1);
        }

        ans = min(ans, ans1+sol(k));
    }

    return dp[i] = ans;
}

void solve() {
    cin >> n;

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

    cout << sol(0) << endl;

    
}

int main() {
    ios::sync_with_stdio(false); cin.tie(0);

    // freopen("in.in", "r", stdin);
    //freopen("out.out", "w", stdout);

    ii tt = 1;
    // cin >> tt;
    while(tt--) solve();

}

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