Submission #1273367

#	Time	Username	Problem	Language	Result	Execution time	Memory
1273367		Tymond	Group Photo (JOI21_ho_t3)	C++20	0 / 100	1 ms	568 KiB

Main

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::high_resolution_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

struct pair_hash{
  size_t operator()(const pair<int,int>&x)const{
    return hash<long long>()(((long long)x.first)^(((long long)x.second)<<32));
  }
};

const int MAXN = 5e3 + 7;
const int INF = 1e9;
ll dp[MAXN];
int pre[MAXN][MAXN];
int post[MAXN][MAXN];
int Pos[MAXN];
int A[MAXN];
int n;

//ile jest na prawo, takich które będą przechodzić na lewo
int countOnRight(int x, int pr){
    int p = Pos[x];
    return post[p][n] - (post[p][x] - post[p][pr]);
}

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

    for(int i = n; i >= 1; i--){
        dp[i] = INF;
        for(int j = 1; j <= n; j++){
            post[i][j] = post[i + 1][j];
            if(j >= A[i]){
                post[i][j]++;
            }
        }
    }
    dp[0] = 0;
    for(int i = 0; i < n; i++){
        //policzyłeś dla i
        ll curr = dp[i];
        for(int j = n; j > i; j--){
            curr = (ll)curr + countOnRight(j, i);
        }
        dp[n] = min(dp[n], curr);

        for(int j = n; j > i + 1; j--){
            //z aktualnego rozw. usuwasz j
            curr = (ll)curr - countOnRight(j, i);
            dp[j - 1] = min(dp[j - 1], curr);
        }
    }

    // for(int i = n; i >= 1; i--){
    //     cout << i << ' ' << dp[i] << '\n';
    // }

    cout << dp[n] << '\n';
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
    
    int t = 1;
    //cin >> t;
    while(t--){
        solve();
    }

    return 0;
}

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