Submission #173649

#	Time	Username	Problem	Language	Result	Execution time	Memory
173649		Nucleist	Palindromes (APIO14_palindrome)	C++14	8 / 100	1090 ms	8768 KiB

palindrome

#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())
struct greateri
{
    template<class T>
    bool operator()(T const &a, T const &b) const { return a > b; }
};
vector<ll> rabin_karp(string const& s, string const& t) {
    const ll p = 31; 
    const ll m = 1e9 + 9;
    ll S = s.size(), T = t.size();

    vector<long long> p_pow(max(S, T)); 
    p_pow[0] = 1; 
    for (ll i = 1; i < (ll)p_pow.size(); i++) 
        p_pow[i] = (p_pow[i-1] * p) % m;

    vector<long long> h(T + 1, 0); 
    for (ll i = 0; i < T; i++)
        h[i+1] = (h[i] + (t[i] - 'a' + 1) * p_pow[i]) % m; 
    long long h_s = 0; 
    for (ll i = 0; i < S; i++) 
        h_s = (h_s + (s[i] - 'a' + 1) * p_pow[i]) % m; 

    vector<ll> occurences;
    for (ll i = 0; i + S - 1 < T; i++) { 
        long long cur_h = (h[i+S] + m - h[i]) % m; 
        if (cur_h == h_s * p_pow[i] % m)
            occurences.push_back(i);
    }
    return occurences;
}
int main()
{
  //flash;
  string a;
  cin>>a;
  ll ans=0;
  for (ll i = 0; i < a.size(); ++i)
  {
    for (ll j = i; j < a.size(); ++j)
    {
      string dol;
      ll ka=0;
      for (ll k = i; k <= j; ++k)
      {
        dol+=a[k];
      }
      string hey=dol;
      reverse(hey.begin(),hey.end());
      if(hey==dol)
      {
      ve hi = rabin_karp(dol,a);
      ka=hi.size();
      ans=max(ans,ka*(j-i+1));
      }
    }
  }
  cout<<ans;
  return 0;
}
//code the AC sol !
// BS/queue/map

Compilation message (stderr)

palindrome.cpp:4:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("O3")
 
palindrome.cpp:5:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("unroll-loops")
 
palindrome.cpp: In function 'int main()':
palindrome.cpp:55:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (ll i = 0; i < a.size(); ++i)
                  ~~^~~~~~~~~~
palindrome.cpp:57:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (ll j = i; j < a.size(); ++j)
                    ~~^~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 26
• Subtask 5: 0 / 27