Submission #914381

#	Time	Username	Problem	Language	Result	Execution time	Memory
914381		mychecksedad	Group Photo (JOI21_ho_t3)	C++17	100 / 100	314 ms	271980 KiB

Main

/* Author : Mychecksdead  */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
const int N = 5000+100, M = 1e5+10, K = 52, MX = 30;

int n, a[N], dp[N][N], C[N][N];
vector<int> S[N];
void solve(){
  cin >> n;
  for(int i = 1; i <= n; ++i) cin >> a[i];

  for(int i = 0; i <= n; ++i) for(int j = 0; j <=n; ++j) dp[i][j] = MOD;
  dp[0][0] = 0;

  for(int i = 1; i <= n ;++i){
    for(int j = 0; j < n; ++j){
      if(a[i] > j) S[j].pb(a[i]);
    }
  }

  // for(int i = 0 ; i < n; ++i){
  //   for(int x: S[i]) cout << x << ' ';
  //   en;
  // }

  for(int i = 0; i < n; ++i){
    C[0][S[0][i]] = i;
    for(int j = i + 1; j < n; ++j){
      if(S[0][j] < S[0][i]) C[0][S[0][i]]--;
    }
  }

  for(int i = 1; i < n; ++i){
    bool f = 0;
    for(int j = 0; j < n - i + 1; ++j){
      if(S[i - 1][j] == i) f = 1;
      else{
        if(f) C[i][S[i][j - 1]] = C[i - 1][S[i - 1][j]] - 1;
        else C[i][S[i][j]] = C[i - 1][S[i - 1][j]] + 1;
      }
    }
  }

  // for(int i = 0; i < n; ++i){
  //   for(int j = 0; j < i; ++j) cout << 0 << ' ';
  //   for(int j = 0; j < n-i; ++j) cout << C[i][j+1+i] << ' ';
  //   en; 
  // }


  for(int i = 1; i <= n; ++i){
    for(int j = 1; j <= i; ++j){
      if(j == i){
        for(int l = 0; l < i; ++l)
          dp[i][j] = min(dp[i][j], dp[i - 1][l] + C[j - 1][i]);
      }else dp[i][j] = dp[i - 1][j] + C[j - 1][i];
      // cout << dp[i][j] << ' ';
    }
    // en;
  }
  int ans = MOD;
  for(int i = 1; i <= n; ++i) ans = min(ans, dp[n][i]);
  cout << ans;
}



int main(){
  cin.tie(0); ios::sync_with_stdio(0);
  int tt = 1, aa;
  // freopen("in.txt", "r", stdin);
  // freopen("out.txt", "w", stdout);
  // cin >> tt;
  while(tt--){
    solve();
    en;
  }
  cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
  return 0;
} 

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:76:15: warning: unused variable 'aa' [-Wunused-variable]
   76 |   int tt = 1, aa;
      |               ^~

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