Finding Borders

#include <bits/stdc++.h>
 
using namespace std;
 
// BeginCodeSnip{Hashing Template from Module}
class HashedString {
  private:
	// change M and B if you want
	static const long long M = 1e9 + 9;
	static const long long B = 9973;
 
	// pow[i] contains B^i % M
	static vector<long long> pow;
 
	// p_hash[i] is the hash of the first i characters of the given string
	vector<long long> p_hash;
 
  public:
	HashedString(const string &s) : p_hash(s.size() + 1) {
		while (pow.size() <= s.size()) { pow.push_back((pow.back() * B) % M); }
 
		p_hash[0] = 0;
		for (int i = 0; i < s.size(); i++) {
			p_hash[i + 1] = ((p_hash[i] * B) % M + s[i]) % M;
		}
	}
 
	long long get_hash(int start, int end) {
		long long raw_val = (p_hash[end + 1] - (p_hash[start] * pow[end - start + 1]));
		return (raw_val % M + M) % M;
	}
};
vector<long long> HashedString::pow = {1};
// EndCodeSnip
 
int main() {
	string s;
	cin >> s;
 
	HashedString pref(s);
	for (int i = 0; i < (int)s.size() - 1; i++) {
		if (pref.get_hash(0, i) ==
		    pref.get_hash((int)s.size() - i - 1, (int)s.size() - 1)) {
			cout << i + 1 << ' ';
		}
	}
}