Submission #845215

#	Time	Username	Problem	Language	Result	Execution time	Memory
845215		vjudge1	Trener (COCI20_trener)	C++17	110 / 110	1000 ms	132688 KiB

trener

/* 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 = 2000, M = 1e5+10, K = 18;



ll n, k, dp[N][N], H[N][N], p[N];
string s[N][N];
  
bool subseq(int i, int j, int i1, int j1){
  ll h = H[i][j];
  ll h1 = H[i1][j1];
  if((h * p[1]) % MOD == (h1 - (s[i1][j1][0] - 'a' + 1) + MOD) % MOD) return 1;
  if(h == (((h1 - (s[i1][j1][i1 - 1] - 'a' + 1) * p[i1 - 1]) % MOD) + MOD) % MOD) return 1;
  return 0;
}

void solve(){
  p[0] = 1;
  for(int i = 1; i < N; ++i) p[i] = (p[i-1] * 37) % MOD;
  cin >> n >> k;
  for(int i = 1; i <= n; ++i){
    for(int j = 1; j <= k; ++j){
      cin >> s[i][j];
      H[i][j] = 0;
      for(int l = 0; l < i; ++l){
        H[i][j] += p[l] * (s[i][j][l] - 'a' + 1);
        H[i][j] %= MOD;
      }
    }
  }
  
  for(int i = 1; i <= n; ++i) for(int j = 0; j <= k; ++j) dp[i][j] = (n == i);
  for(int i = n - 1; i >= 1; --i){
    for(int j = 1; j <= k; ++j){
      for(int to = 1; to <= k; ++to){
        if(subseq(i, j, i + 1, to)){
          dp[i][j] += dp[i + 1][to];
          dp[i][j] -= dp[i][j] >= MOD ? MOD : 0;
        }
      }
    }
  }
  ll ans = 0;
  for(int i = 1; i <= k; ++i) (ans+=dp[1][i])%=MOD;
  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)

trener.cpp: In function 'int main()':
trener.cpp:59:15: warning: unused variable 'aa' [-Wunused-variable]
   59 |   int tt = 1, aa;
      |               ^~

• Subtask 1: 22 / 22
• Subtask 2: 33 / 33
• Subtask 3: 55 / 55