Cod sursa(job #3207167)

Utilizator not_anduAndu Scheusan not_andu Data 25 februarie 2024 13:33:35
Problema PScPld Scor 100
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 1.18 kb
#include <bits/stdc++.h>

using namespace std;

#define INFILE "pscpld.in"
#define OUTFILE "pscpld.out"

typedef long long ll;

vector<int> manacher(string s){
    int n = s.length();
    vector<int> palindrom(n);
    int left = 0, right = 0;
    for(int i = 0; i < n; ++i){
        if(i < right){
            palindrom[i] = min(right - i + 1, palindrom[left + right - i]);
        }
        while(i - palindrom[i] >= 0 && i + palindrom[i] < n && s[i - palindrom[i]] == s[i + palindrom[i]]){
            ++palindrom[i];
        }
        if(i + palindrom[i] > right){
            left = i - palindrom[i] + 1;
            right = i + palindrom[i] - 1;
        }
    }
    return palindrom;
}

void solve(){

    string aux; cin >> aux;
    string s;

    for(int i = 0; i < aux.length(); ++i){
        s += '#';
        s += aux[i];
    }
    s += '#';

    ll ans = 0;
    vector<int> palindrom = manacher(s);

    for(int i = 0; i < palindrom.size(); ++i){
        ans += (palindrom[i] / 2);
    }

    cout << ans << '\n';

}

int main(){
    ios_base::sync_with_stdio(false);
    freopen(INFILE, "r", stdin);
    freopen(OUTFILE, "w", stdout);
    cin.tie(0), cout.tie(0);
    solve();
    return 0;
}