Cod sursa(job #3186887)

Utilizator MegaCoderMinoiu Teodor Mihai MegaCoder Data 26 decembrie 2023 12:31:49
Problema PScPld Scor 30
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 0.94 kb
#include<fstream>
std::ifstream fin("pscpld.in");
std::ofstream fout("pscpld.out");
std::string initial;
char s[2000005];
int vec[2000005];
long long size;
inline void precalc()
{
    fin>>initial;
    int aux=initial.size();
    for(int index=0; index<aux; ++index)
    {
        s[size++]='#';
        s[size++]=initial[index];
    }
    s[size++]='#';
}

inline void manacher()
{
    int ans=0;
    int c=0, r=0;
    for(int index=0; index<=size; ++index)
    {
        int sim=2*c-index;
        vec[index]=std::max(0, std::min(vec[sim], r-index));
        while(s[index+vec[index]]==s[index-vec[index]] && index+vec[index]<=size && index-vec[index]>=0)
            ++vec[index];
        --vec[index];
        ans+=(vec[index]+1)/2;
        if(index+vec[index]>r)
        {
            r=index+vec[index];
            c=index;
        }
    }
    fout<<ans;
}
int main()
{
    std::ios_base::sync_with_stdio(false);
    precalc();
    manacher();
    return 0;
}