04-algorithms_on_strings/04-suffix_array/01-kmp/kmp.cpp


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#include <cstdio>
#include <iostream>
#include <string>
#include <vector>

using std::cin;
using std::string;
using std::vector;

vector<int> find_pattern(const string& pattern, const string& text)
{
    vector<int> result;
    string s = pattern + "$" + text;
    vector<int> prefixes(s.size());
    int border = 0;
    int ps = pattern.size();

    for (int i = 1; i < s.size(); i++) {
        while ((border > 0) && (s[i] != s[border]))
            border = prefixes[border - 1];
        prefixes[i] = border = ((s[i] == s[border]) ? (border + 1) : 0);
        if (border == ps)
            result.push_back(i - 2 * ps);
    }

    return result;
}

int main() {
  string pattern, text;
  cin >> pattern;
  cin >> text;
  vector<int> result = find_pattern(pattern, text);
  for (int i = 0; i < result.size(); ++i) {
    printf("%d ", result[i]);
  }
  printf("\n");
  return 0;
}