z-function.cpp

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

template <class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define int long long int
#define endl '\n'
#define pb push_back
#define pi pair<int, int>
#define pii pair<int, pi>
#define fir first
#define sec second
#define MAXN 2001
#define mod 1000000007

vector<int> z_function(string &s)
{
  int n = s.size();
  vector<int> z(n);
  z[0] = n;
  for (int i = 1, l = 0, r = 0; i < n; i++)
  {
    if (i <= r)
      z[i] = min(r - i + 1, z[i - l]);
    while (i + z[i] < n && s[z[i]] == s[i + z[i]])
      z[i]++;
    if (i + z[i] - 1 > r)
      l = i, r = i + z[i] - 1;
  }
  return z;
}
signed main()
{
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  string s;
  cin >> s;
  vector<int> z = z_function(s);
}
// z-function
// calcula para cada i:
// z[i] = o tamanho de lcp(s, s.substr(i, n - i))
// lcp -> longest comom prefix