Submission #928890

#	Time	Username	Problem	Language	Result	Execution time	Memory
928890		UmairAhmadMirza	Necklace (Subtask 1-3) (BOI19_necklace1)	C++17	25 / 85	144 ms	8088 KiB

necklace

#include <iostream>
using namespace std;
#define int long long
int const N=405;
int const mod=2e9+7;
int const base=1e5+237;
int hsh1[N][N];
int hsh2[N][N];
int r_hsh1[N][N];
int r_hsh2[N][N];
int min_hsh1[N][N];
int min_hsh2[N][N];
// map<int,bool> mp1;
// map<int,bool> mp2;
int pw[N];
string a,b;
void make_hash1(){
  int n=a.length();
  for(int i=1;i<=n;i++){
    int h1=0;
    for(int j=i;j<=n;j++){
      h1*=base;
      h1%=mod;
      h1+=a[j-1];
      h1%=mod;
      hsh1[i][j]=h1;
    }
  }
  for(int i=n;i>=1;i--){
    int h1=0;
    for(int j=i;j>=1;j--){
      h1*=base;
      h1%=mod;
      h1+=a[j-1];
      h1%=mod;
      r_hsh1[j][i]=h1;
    }
  }
}
void make_hash2(){
  int n=b.length();
  for(int i=1;i<=n;i++){
    int h1=0;
    for(int j=i;j<=n;j++){
      h1*=base;
      h1%=mod;
      h1+=b[j-1];
      h1%=mod;
      hsh2[i][j]=h1;
    }
  }
  for(int i=n;i>=1;i--){
    int h1=0;
    for(int j=i;j>=1;j--){
      h1*=base;
      h1%=mod;
      h1+=b[j-1];
      h1%=mod;
      r_hsh2[j][i]=h1;
    }
  }
}
void set_hsh1(){
  int n=a.length();
  int h=0;
  for(int i=1;i<=n;i++)
    for(int j=i;j<=n;j++){
      min_hsh1[i][j]=hsh1[i][j];
      for(int k=i;k<=j;k++){
        h=(hsh1[k][j]*pw[k-i])%mod;
        h+=hsh1[i][k-1];
        h%=mod;
        min_hsh1[i][j]=min(min_hsh1[i][j],h);
      }
      // cout<<i<<' '<<j<<' '<<min_hsh1[i][j]<<endl;
    }
  
  for(int i=1;i<=n;i++)
    for(int j=i;j<=n;j++){
      // min_hsh1[i][j]=hsh2[i][j];
      for(int k=i;k<=j;k++){
        h=(r_hsh1[i][k]*pw[j-k])%mod;
        h+=r_hsh1[k+1][j];
        h%=mod;
        min_hsh1[i][j]=min(min_hsh1[i][j],h);
      }
      // cout<<i<<' '<<j<<' '<<min_hsh1[i][j]<<endl;
    }
}
void set_hsh2(){
  int n=b.length();
  int h=0;
  for(int i=1;i<=n;i++)
    for(int j=i;j<=n;j++){
      min_hsh2[i][j]=hsh2[i][j];
      for(int k=i;k<=j;k++){
        h=(hsh2[k][j]*pw[k-i])%mod;
        h+=hsh2[i][k-1];
        h%=mod;
        min_hsh2[i][j]=min(min_hsh2[i][j],h);
      }
      // cout<<i<<' '<<j<<' '<<min_hsh2[i][j]<<endl;
    }
  
  for(int i=1;i<=n;i++)
    for(int j=i;j<=n;j++){
      for(int k=i;k<=j;k++){
        h=(r_hsh2[i][k]*pw[j-k])%mod;
        h+=r_hsh2[k+1][j];
        h%=mod;
        min_hsh2[i][j]=min(min_hsh2[i][j],h);
      }
      // cout<<i<<' '<<j<<' '<<min_hsh2[i][j]<<endl;
    }
}
void pwer(){
  pw[0]=1;
  for(int i=1;i<N;i++)
    pw[i]=(pw[i-1]*base)%mod;
}

signed main() 
{
  cin>>a>>b;
  pwer();
  make_hash1();
  make_hash2();
  set_hsh1();
  set_hsh2();
  int n=a.length();
  int m=b.length();
  for(int l=n-1;l>=0;l--)
    for(int i=1;i<=(n-l);i++)
      for(int j=1;j<=m-l;j++){
        if(min_hsh1[i][i+l]==min_hsh2[j][j+l]){
          cout<<l+1<<endl;
          cout<<i-1<<' '<<j-1<<endl;
          return 0;
        }
      }
}

• Subtask 1: 25 / 25
• Subtask 2: 0 / 20
• Subtask 3: 0 / 40