Submission #240189

#	Time	Username	Problem	Language	Result	Execution time	Memory
240189		Nucleist	Palindromic Partitions (CEOI17_palindromic)	C++14	60 / 100	396 ms	131072 KiB

palindromic

#include <bits/stdc++.h> 
using namespace std; 
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#define flash ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define debug(x) cerr << " - " << #x << ": " << x << endl;
#define debugs(x, y) cerr << " - " << #x << ": " << x << " " << #y << ": " << y << endl;
#define all(x) (x).begin(),(x).end()
#define sz(x) (ll)x.size()
#define ll long long
#define INF 1000000000
#define MOD 1000000007
#define pb push_back
#define ve vector<ll>
#define dos pair<ll,ll>
#define vedos vector<dos>
#define rand mt19937 rng(chrono::steady_clock::now().time_since_epoch().count())
#define EPS 0.000001
struct greateri
{
    template<class T>
    bool operator()(T const &a, T const &b) const { return a > b; }
};
void setIO(string s) {
  ios_base::sync_with_stdio(0); cin.tie(0); 
  freopen((s+".in").c_str(),"r",stdin);
  freopen((s+".out").c_str(),"w",stdout);
}
ve pi;
ll mi=1e9+9;
ve compute_hash(string const& s) {
    const ll p = 31;
    const ll m = 1e9 + 9;
    long long hash_value = 0;
    long long p_pow = 1;
    ve cur;
    for (char c : s) {
        hash_value = (hash_value + (c - 'a' + 1) * p_pow) % m;
        pi.pb(p_pow);
        p_pow = (p_pow * p) % m;
        cur.pb(hash_value);
    }
    return cur;
}
ve compute_hash1(string const& s) {
    const ll p = 31;
    const ll m = 1e9 + 9;
    long long hash_value = 0;
    long long p_pow = 1;
    ve cur;
    for (ll i = s.size()-1; i >= 0; --i)
    {
      char c=s[i];
      hash_value = (hash_value*31)%m; 
      hash_value = (hash_value + (c - 'a' + 1)) % m;
      p_pow = (p_pow * p) % m;
      cur.pb(hash_value);
    }
    return cur;
}
int main()
{
  //freopen("tit.txt","r",stdin);
  //freopen("out","w",stdout);
  flash;
  ll nb;
  cin>>nb;
  ve now,now1;
  while(nb--){
    string ka;
    cin>>ka;
    now=compute_hash(ka);
    now1=compute_hash1(ka);
    reverse(all(now1));
    ll n=sz(ka);
    ll last=INF;
    ll last1=INF;
    ll ans=0;
    ll kobr=n;
    for (int i = 0; i < ka.size()/2; ++i)
    {
      ll cur=0,cur1=0;
      if(last!=INF){
        cur=(now1[n-i-1]-((ll)((now1[n-last1-1]*pi[i-last1]))%mi)+mi)%mi;
        cur=(ll)((cur*pi[last1+1]))%mi;
        cur1=(now[i]-now[last]+mi)%mi;
      }
      else{
        cur=(now1[n-i-1]);
        cur1=(now[i]);
      }
      if(cur==cur1){
        if(last!=INF)kobr-=(i-last)*2;
        else kobr-=(i+1)*2;
        last=i;
        last1=i;
        ans+=2;
      }
    }
    if(kobr)ans++;
    cout<<ans<<'\n';
  }
  return 0;
}
//code the AC sol !
// BS/queue/map

Compilation message (stderr)

palindromic.cpp:4:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("O3")
 
palindromic.cpp:5:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("unroll-loops")
 
palindromic.cpp: In function 'int main()':
palindromic.cpp:81:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < ka.size()/2; ++i)
                     ~~^~~~~~~~~~~~~
palindromic.cpp: In function 'void setIO(std::__cxx11::string)':
palindromic.cpp:27:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen((s+".in").c_str(),"r",stdin);
   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
palindromic.cpp:28:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen((s+".out").c_str(),"w",stdout);
   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 0 / 40