Cod sursa(job #3318135)

Utilizator TimofeiFilipTimofei Filip Emanuel TimofeiFilip Data 27 octombrie 2025 11:55:33
Problema Potrivirea sirurilor Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.74 kb
#include <bits/stdc++.h>
using namespace std;

const int NMAX = 2000005;
const long long BASE = 131;     
const long long MOD = 1000000007;
const char HASHER = '0';

char A[NMAX], B[NMAX];
long long powers[NMAX];

void PrecomputePowers(int n) {
    powers[0] = 1;
    for (int i = 1; i <= n; i++)
        powers[i] = (powers[i - 1] * BASE) % MOD;
}

long long HashEntireString(const char s[], int n) {
    long long h = 0;
    for (int i = 0; i < n; i++)
        h = (h + 1LL * powers[n - i - 1] * (s[i] - HASHER)) % MOD;
    return h;
}

long long getNextHash(long long current_hash, int n, char oldChar, char newChar) {
    current_hash = (current_hash - (1LL * powers[n - 1] * (oldChar - HASHER))) % MOD;
    if (current_hash < 0) current_hash += MOD;
    current_hash = (current_hash * BASE) % MOD;
    current_hash = (current_hash + (newChar - HASHER)) % MOD;
    return current_hash;
}

vector<int> RabinKarp(const char a[], const char b[]) {
    vector<int> positions;
    int n = strlen(a), m = strlen(b);
    if (n > m) return positions;

    long long hash_A = HashEntireString(a, n);
    long long current_hash = HashEntireString(b, n);

    if (hash_A == current_hash)
        positions.push_back(0);

    for (int i = n; i < m; i++) {
        current_hash = getNextHash(current_hash, n, b[i - n], b[i]);
        if (current_hash == hash_A)
            positions.push_back(i - n + 1);
    }

    return positions;
}

int main() {
    freopen("strmatch.in", "r", stdin);
    freopen("strmatch.out", "w", stdout);
    cin >> A >> B;

    PrecomputePowers(strlen(A) + 1);

    vector<int> ans = RabinKarp(A, B);

    cout << ans.size() << "\n";
    for (int i = 0; i < min((int)ans.size(), 1000); i++)
        cout << ans[i] << " ";
    cout << "\n";

    return 0;
}