Submission #1112785

#	Time	Username	Problem	Language	Result	Execution time	Memory
1112785		groshi	Palindromes (APIO14_palindrome)	C++17	100 / 100	700 ms	72336 KiB

palindrome

#include <bits/stdc++.h>
#define int long long
using namespace std;
int maxx=1e9;
int pierw[2]={2137,601};
int mod[2]={maxx+7,maxx+9};
int potegi[400000][2];
int hasze[400000][2];
int dl[400000];
bool odw[400000];
int licze[400000];
int essa[800000];
int ktory=1;
map<pair<int,int>,int> mapka;
vector<int> Q[400000];
pair<int,int> licz(int x,int y)
{
    int hasz1=(hasze[y][0]-hasze[x-1][0]*potegi[y-x+1][0]+mod[0]*mod[0])%mod[0];
    int hasz2=(hasze[y][1]-hasze[x-1][1]*potegi[y-x+1][1]+mod[1]*mod[1])%mod[1];
    return {hasz1,hasz2};
}
int szukaj(pair<int,int> hasze,int x,int y)
{
    if(mapka.find(hasze)!=mapka.end())
        return mapka[hasze];
    mapka[hasze]=ktory;
    dl[ktory]=y-x+1;
    ktory++;
    return ktory-1;
}
int dfs(int x)
{
    if(odw[x])
        return licze[x];
    odw[x]=1;
    for(int i=0;i<Q[x].size();i++)
        licze[x]+=dfs(Q[x][i]);
    return licze[x];
}
void reku(int x,int y)
{
    pair<int,int> hasz=licz(x,y);
    int ktory=szukaj(hasz,x,y);
    if(odw[ktory] || x+1>y-1)
        return;
    odw[ktory]=1;
    pair<int,int> hasz2=licz(x+1,y-1);
    int ktory2=szukaj(hasz2,x+1,y-1);
    Q[ktory2].push_back(ktory);
    reku(x+1,y-1);
}
int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    string s;
    cin>>s;
    potegi[0][0]=1;
    potegi[0][1]=1;
    for(int i=1;i<=s.length();i++)
        for(int j=0;j<2;j++)
            potegi[i][j]=(potegi[i-1][j]*pierw[j])%mod[j];
    for(int i=0;i<s.length();i++)
        for(int j=0;j<2;j++)
        {
            if(i!=0)
                hasze[i][j]=(hasze[i-1][j]*pierw[j]+(s[i]-'a'+1))%mod[j];
            else hasze[i][j]=(s[i]-'a'+1);
        }
    vector<char> pomoc;
    pomoc.push_back(s[0]);
    for(int i=1;i<s.length();i++)
        pomoc.push_back('.'),pomoc.push_back(s[i]);
    int n=s.length();
    int r=-1;
    int k=-1;
    for(int i=0;i<2*n-1;i++)
    {
        if(i<=r)
            essa[i]=min(essa[2*k-i],r-i);
        while(i-essa[i]-1>=0 && i+essa[i]+1<2*n-1 && pomoc[i-essa[i]-1]==pomoc[i+essa[i]+1])
            essa[i]++;
        if(r<i+essa[i])
            r=i+essa[i],k=i;
        int dl,x,y;
        if(i%2==1)
        {
            dl=(essa[i]+1)/2;
            x=i/2-dl+1;
            y=i/2+dl;
        }
        else{
            dl=essa[i]/2;
            x=i/2-dl;
            y=i/2+dl;
        }
        if(x>y)
            continue;
        pair<int,int> hasz=licz(x,y);
        licze[szukaj(hasz,x,y)]++;
        reku(x,y);
    }
    for(int i=0;i<=ktory;i++)
        odw[i]=0;
    int wynik=0;
    for(int i=1;i<ktory;i++)
        wynik=max(wynik,dl[i]*dfs(i));
    cout<<wynik;
    return 0;
}

Compilation message (stderr)

palindrome.cpp: In function 'long long int dfs(long long int)':
palindrome.cpp:36:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |     for(int i=0;i<Q[x].size();i++)
      |                 ~^~~~~~~~~~~~
palindrome.cpp: In function 'int32_t main()':
palindrome.cpp:61:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |     for(int i=1;i<=s.length();i++)
      |                 ~^~~~~~~~~~~~
palindrome.cpp:64:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |     for(int i=0;i<s.length();i++)
      |                 ~^~~~~~~~~~~
palindrome.cpp:73:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |     for(int i=1;i<s.length();i++)
      |                 ~^~~~~~~~~~~

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