Envío 2044

Código

#include <bits/stdc++.h>

using namespace std;

int main() {
    string s;
    cin >> s;
    int left = 0;
    int right = s.size();
    vector<int> prefixSuffixTable(right, 0);
    for (int i = 1; i < right; i++) {
        while(left > 0 and s[left] != s[i]) {
            left = prefixSuffixTable[left-1];
        }
        if (s[left] == s[i]){
            left++;
        }
        prefixSuffixTable[i] = left;
    }
    cout << prefixSuffixTable[right-1] << endl;

}