Submission #709522

#	Time	Username	Problem	Language	Result	Execution time	Memory
709522		epicci23	Group Photo (JOI21_ho_t3)	C++17	100 / 100	752 ms	196428 KiB

Main

#include "bits/stdc++.h"
#pragma optimize ("Bismillahirrahmanirrahim")
using namespace std;
#define pb push_back
#define ff first
#define ss second
#define endl "\n" 
#define int long long
#define double long double
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define what_is(x) cerr << #x << " is " << x << endl;
//#define m (l+r)/2
constexpr int N=200005;
constexpr int MOD=1000000007;
constexpr int  INF2 = LLONG_MAX;
constexpr int INF=(int)1e18;
constexpr int LOG=30;
typedef pair<int,int> pii;
typedef tuple<int,int,int> tp;
typedef priority_queue<pii,vector<pii>,greater<pii>> min_pq;
typedef priority_queue<pii> max_pq;
typedef long long ll;
//to think//
/*
 * graph approach
 * dp
 * dividing the problem to smaller statements
 * finding the real constraint
 * sqrt decomposition
 * greedy approach
 * pigeonhole principle
 * rewriting the problem/equality 
 * bitwise approaches
 * binary search if monotonic
 * divide and conquer
 * combinatorics
 * inclusion - exclusion
 * think like bfs
*/



inline int in()
{
  int x;cin >> x;
  return x;
}

inline string in2()
{
  string x;cin >> x;
  return x;
}


void solve()
{
  int n=in();
  int arr[n+2];
  for(int i=1;i<=n;i++) arr[i]=in();
  int dp[n+2];
  for(int i=1;i<=n;i++) dp[i]=INF;
  dp[0]=0;

  int pre[n+2][n+2];
  
  for(int i=0;i<=n;i++) pre[0][i]=pre[i][0]=0;

  vector<int> mark(n+2,0);
  
  for(int i=1;i<=n;i++)
  {
    int cur=0;
    for(int j=1;j<=n;j++)
    {
      cur+=mark[j];
      pre[arr[i]][j]=cur;
     // cout << "i: " << arr[i] << " " <<" j: " << j << " " << pre[arr[i]][j] << endl;
    }
    mark[arr[i]]=1;
  }
   
  int pre2[n+2];
  pre2[0]=0;
  for(int i=1;i<=n;i++) pre2[i]=pre2[i-1] + pre[i][i];

  for(int j=1;j<=n;j++)
    for(int i=1;i<=n;i++) 
     pre[i][j]+=pre[i-1][j];
  
  for(int i=0;i<n;i++)
  {
    for(int j=i+1;j<=n;j++)
    {
      dp[j]=min(dp[j],dp[i] + (pre2[j]-pre2[i]) - (pre[j][i]-pre[i][i]) + (pre[j][n]-pre[i][n]) - (pre[j][j]-pre[i][j]) );
    }
  }

  
  cout << dp[n] << endl;
}

int32_t main(){
   

     cin.tie(0); ios::sync_with_stdio(0);
     cout << fixed <<  setprecision(15);
   
   int t=1;//cin>> t;
 
 for(int i=1;i<=t;i++)
 {
  //  cout << "Case #" << i << ": ";
    solve();
 }
 
 return 0;
}

Compilation message (stderr)

Main.cpp:2: warning: ignoring '#pragma optimize ' [-Wunknown-pragmas]
    2 | #pragma optimize ("Bismillahirrahmanirrahim")
      |

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