제출 #1278731

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1278731		dosts	Group Photo (JOI21_ho_t3)	C++20	100 / 100	273 ms	636 KiB

Main

#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
#define int long long
#define pii pair<int,int>
#define vi vector<int>
#define ff first
#define ss second
#define sp << " " <<
#define all(x) x.begin(),x.end()
#define big(x) ((int)(x.size()))
using namespace std;
const int MOD = 1e9+7, LIM = 1e6+1, inf = 2e18;

const int N = 2e5+1;



struct FT {
    vi bit;
    int n;
    FT(int nn) {
        n = nn;
        bit.assign(n + 1, 0);
    }
    void put(int p, int v) {
        for (int i = p; i <= n; i += i & -i) bit[i] += v;
    }
    int get(int p) {
        int ans = 0;
        for (int i = p; i > 0; i -= i & -i) ans += bit[i];
        return ans;
    }
    int get(int l, int r) {
        return get(r) - get(l - 1);
    }

    void reset() {
        bit.assign(n+1,0);
    }
};
void solve() {
    int n;
    cin >> n;
    vi a(n+1),pos(n+1);
    for (int i=1;i<=n;i++) cin >> a[i];
    for (int i=1;i<=n;i++) pos[a[i]] = i;
    vi dp(n+1,inf);
    dp[0] = 0;
    vi pref(n+1,0);
    FT ft(n);
    for (int i=0;i<n;i++) {
        //ilk i yere i sayıyı yerleştirdim
        int cost = 0;
        pref.assign(n+1,0);
        for (int j = 1;j<=n;j++) pref[j] = pref[j-1]+(a[j] > i);
        ft.reset();
        for (int j = i+1;j<=n;j++) {
            //[i+1..j] gelcek şimdi
            cost-=ft.get(pos[j]+1,n);
            cost+=pref[pos[j]-1];
            dp[j] = min(dp[j],dp[i]+cost);
            ft.put(pos[j],1);
        }
    }
    cout << dp[n] << '\n';
}   

signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    #ifdef Dodi
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    #endif
    int t = 1;
    //cin >> t;
    while (t --> 0) solve();
}

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