Cod sursa(job #2798851)

Utilizator bogdanvladmihaiBogdan Vlad-Mihai bogdanvladmihai Data 11 noiembrie 2021 23:54:25
Problema PScPld Scor 70
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 1.02 kb
#include <bits/stdc++.h>

using namespace std;

ifstream in("pscpld.in");
ofstream out("pscpld.out");

using ll = long long;

vector<int> Manacher(string &s) {
  vector<int> pal((int)s.size());
  int l = -1, r = -1;
  for (int i = 0; i < (int)s.size(); i++) {
    if (i > r)
      pal[i] = 1;
    else
      pal[i] = min(r - i + 1, pal[l + r - i]);
    while (i - pal[i] >= 0 && i + pal[i] < (int)s.size() && s[i - pal[i]] == s[i + pal[i]])
      pal[i]++;
    pal[i]--;
    if (i + pal[i] > r) {
      r = i + pal[i];
      l = i - pal[i];
    }
  }
  return pal;
}

int main() {
  in.tie(NULL);
  out.tie(NULL);
  ios_base::sync_with_stdio(false);
  string s; in >> s;
  string t;
  t += 'W';
  for (char c : s) {
    t += c;
    t += 'W';
  }
  auto pal = Manacher(t);
  ll ans = (ll)0;
//  for (char x : t) cerr << x << " ";
//  cerr << "\n";
//  for (int x : pal) cerr << x << " ";
  for (int i = 0; i < (int)t.size(); i++)
    ans += (ll)(1 + pal[i]) / 2;
  out << ans << "\n";
  return 0;
}