Submission #173651

#	Time	Username	Problem	Language	Result	Execution time	Memory
173651		Nucleist	Palindromes (APIO14_palindrome)	C++14	8 / 100	1085 ms	12520 KiB

palindrome

#include<bits/stdc++.h> 
using namespace std; 
string substring(string s,int a,int b) 
{ 
    string s1=""; 
    for(int i = a; i < b; i++) 
        s1 = s1 + s[i]; 
          
    return s1; 
} 
vector<string> allPalindromeSubstring(string s) 
{ 
    vector<string> v ; 
    for (float pivot = 0; pivot < s.length(); 
                                 pivot += .5) 
    { 
        float palindromeRadius = pivot -  
                                  (int)pivot; 
        while ((pivot + palindromeRadius) 
         < s.length() && (pivot - palindromeRadius)  
         >= 0 && s[((int)(pivot - palindromeRadius))] 
             == s[((int)(pivot + palindromeRadius))]) 
        { 
  
            v.push_back(substring(s,(int)(pivot -  
                     palindromeRadius), (int)(pivot  
                           + palindromeRadius + 1))); 
            palindromeRadius++; 
        } 
    } 
  
    return v; 
} 
vector<int> rabin_karp(string const& s, string const& t) {
    const int p = 31; 
    const int m = 1e9 + 9;
    int S = s.size(), T = t.size();

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

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

    vector<int> occurences;
    for (int 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() 
{ 
    string a;
    cin>>a;
    vector<string> v = allPalindromeSubstring(a); 
    set<string>aw;
    for(auto it:v)aw.insert(it);
    int ans=0;
    for(auto it:aw)
    {
      ans=max(ans,(int)((rabin_karp(it,a).size())*it.size()));
    }
    cout<<ans;
} 

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