RabinKarp

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

int main()
{
    string s = "the", t = "We implement the algorithm";

    const int  p = 31;
    vector<long long> p_pow(max(s.size(), t.size()));

    p_pow[0] = 1;

    for (size_t i = 1; i<p_pow.size(); ++i) p_pow[i] = p_pow[i - 1] * p; //
    for (size_t i = 0; i<p_pow.size(); ++i) cout << p_pow[i] << endl;

    vector<long long> h(t.size());
    for (size_t i = 0; i<t.size(); ++i)
    {
        h[i] = (t[i] - 'a' + 1) * p_pow[i];
        if (i)  h[i] += h[i - 1];
    }

    for (size_t i = 1; i<h.size(); ++i) cout << endl << h[i];

    long long h_s = 0;
    for (size_t i = 0; i<s.size(); ++i) h_s += (s[i] - 'a' + 1) * p_pow[i];

    cout << endl << h_s << endl;

    for (size_t i = 0; i + s.size() - 1 < t.size(); ++i)
    {
        long long cur_h = h[i + s.length() - 1];
        if (i)  cur_h -= h[i - 1];
        if (cur_h == h_s * p_pow[i])
            cout << i << ' ';
    }

    return 0;
}