29 lines
543 B
C++
29 lines
543 B
C++
#include <string>
|
|
#include <vector>
|
|
using namespace std;
|
|
|
|
int KMP(string &S, string &T) {
|
|
// Generate KMP table
|
|
vector<int> F(T.length() + 1, 0);
|
|
F[0] = -1;
|
|
for (int i = 0; i < T.length(); i++) {
|
|
F[i + 1] = F[i];
|
|
while (F[i + 1] > -1 && T[i] != T[F[i + 1]]) F[i + 1] = F[F[i + 1]];
|
|
F[i + 1]++;
|
|
}
|
|
|
|
// Search
|
|
int i = 0, j = 0;
|
|
while (i < S.length()) {
|
|
if (S[i] == T[j]) {
|
|
i++, j++;
|
|
if (j == T.length()) return i - j; // Found match
|
|
}
|
|
else {
|
|
j = F[j];
|
|
if (j < 0) i++, j++;
|
|
}
|
|
}
|
|
|
|
return -1; // Match not found
|
|
}
|