Submission #770037

#	Time	Username	Problem	Language	Result	Execution time	Memory
770037		bachhoangxuan	Group Photo (JOI21_ho_t3)	C++17	100 / 100	231 ms	196456 KiB

Main

// Judges with GCC >= 12 only needs Ofast
// #pragma GCC optimize("O3,no-stack-protector,fast-math,unroll-loops,tree-vectorize")
// MLE optimization
// #pragma GCC optimize("conserve-stack")
// Old judges
// #pragma GCC target("sse4.2,popcnt,lzcnt,abm,mmx,fma,bmi,bmi2")
// New judges. Test with assert(__builtin_cpu_supports("avx2"));
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")
// Atcoder
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma")
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
- insert(x),erase(x)
- find_by_order(k): return iterator to the k-th smallest element
- order_of_key(x): the number of elements that are strictly smaller
*/
#include<bits/stdc++.h>
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
uniform_real_distribution<> pp(0.0,1.0);
#define int long long
#define ld long double
#define pii pair<int,int>
#define piii pair<pii,int>
#define mpp make_pair
#define fi first
#define se second
const int inf=1e18;
const int mod=1e9+7;
const int maxn=100005;
const int bl=650;
const int maxs=655;
const int maxm=200005;
const int maxq=500005;
const int maxl=20;
const int maxa=250000;
const int root=3;
int power(int a,int n){
    int res=1;
    while(n){
        if(n&1) res=res*a%mod;
        a=a*a%mod;n>>=1;
    }
    return res;
}
const int iroot=power(3,mod-2);
const int base=101;

void solve(){
    int n;cin >> n;
    vector<int> h(n+1,0),dp(n+1,0),c(n+1,0),num(n+1,0);
    vector<vector<int>> cost(n+1,vector<int>(n+1,0));
    for(int i=1;i<=n;i++){int x;cin >> x;h[x]=i;}
    //for(int i=1;i<=n;i++) cout << h[i] << ' ';
    //cout << '\n';
    for(int i=1;i<=n;i++){
        c[i]=c[i-1];
        for(int j=1;j<i;j++) c[i]+=(h[i]>h[j]);
        //cout << c[i] << ' ';
    }
    //cout << '\n';
    for(int i=0;i<n;i++){
        for(int j=1;j<=h[i];j++) num[j]++;
        for(int j=i+1;j<=n;j++) cost[i][j]=cost[i][j-1]+num[h[j]];
        for(int j=i+1;j<=n;j++){
            cost[i][j]=c[j]-c[i]-(j-i)*i+2*cost[i][j];
            //cout << cost[i][j] << ' ';
        }
        //cout << '\n';
    }
    //cout << '\n';
    for(int i=1;i<=n;i++){
        dp[i]=inf;
        for(int j=0;j<i;j++) dp[i]=min(dp[i],dp[j]+cost[j][i]);
    }
    cout << dp[n] << '\n';
}
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);cout.tie(NULL);
    int test=1;//cin >> test;
    while(test--) solve();
}

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