Create kmp.cpp

Changes

1 changed files (+29/-0)

• String/kmp.cpp (new)
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    + #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 + }