Z-array

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
 
int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    
    string s;
    cin >> s;
    int n = s.size();
    vector<int> Z(n, 0);
    
    // The first position Z[0] is the length of the entire string
    Z[0] = n;
    
    int L = 0, R = 0;
    
    for(int i = 1; i < n; i++){
        if(i > R){
            // Case 1: i is outside the current [L, R] window
            L = R = i;
            while(R < n && s[R - L] == s[R]){
                R++;
            }
            Z[i] = R - L;
            R--; // Adjust R to the last matching position
        }
        else{
            // Case 2: i is inside the current [L, R] window
            int k = i - L;
            if(Z[k] < R - i + 1){
                Z[i] = Z[k];
            }
            else{
                L = i;
                while(R < n && s[R - L] == s[R]){
                    R++;
                }
                Z[i] = R - L;
                R--;
            }
        }
    }
    
    // Output the Z-array
    for(int i = 0; i < n; i++){
        cout << Z[i];
        if(i != n-1){
            cout << ' ';
        }
    }
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED