Shared code

#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define sz(x) (int)(x).size()
typedef vector<int> vi;

/**
 * Author: chilli
 * License: CC0
 * Description: z[x] computes the length of the longest common prefix of s[i:] and s, except z[0] = 0. (abacaba -> 0010301)
 * Time: O(n)
 * Status: stress-tested
 */
vi Z(const string& S) {
	vi z(sz(S));
	int l = 0, r = 0;
	rep(i,1,sz(S)) {
		z[i] = min(max(r - i, 0), z[i - l]);
		while (i + z[i] < sz(S) && S[i + z[i]] == S[z[i]])
			z[i]++, l = i, r = i + z[i];
	}
	return z;
}

int main() {
    cin.tie(0)->sync_with_stdio(0);

    string s;
    cin >> s;

    vector<int> z(Z(s));

    for(int sz = 1; sz <= sz(s); sz++) {
        int curr = sz;
        if(curr < sz(s)) {
            curr += z[curr];
        }
        if(curr == sz(s)) cout << sz << " ";
    }

    return 0;
}