KMPMatcher.cpp

Author: lxylxy123456

KMPMatcher.cpp

@@ -0,0 +1,90 @@
+//  
+//  algorithm - some algorithms in "Introduction to Algorithms", third edition
+//  Copyright (C) 2018  lxylxy123456
+//  
+//  This program is free software: you can redistribute it and/or modify
+//  it under the terms of the GNU Affero General Public License as
+//  published by the Free Software Foundation, either version 3 of the
+//  License, or (at your option) any later version.
+//  
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU Affero General Public License for more details.
+//  
+//  You should have received a copy of the GNU Affero General Public License
+//  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//  
+
+#ifndef MAIN
+#define MAIN
+#define MAIN_KMPMatcher
+#endif
+
+#ifndef FUNC_KMPMatcher
+#define FUNC_KMPMatcher
+
+#include "utils.h"
+
+#include "NaiveStringMatcher.cpp"
+
+template <typename T>
+std::vector<size_t> ComputePrefixFunction(const std::vector<T>& P) {
+	size_t m = P.size(); 
+	std::vector<size_t> pi; 
+	pi.push_back(0); 
+	pi.push_back(0); 
+	size_t k = 0; 
+	for (size_t q = 2; q <= m; q++) {
+		while (k && P[k] != P[q - 1])
+			k = pi[k]; 
+		if (P[k] == P[q - 1])
+			k++; 
+		pi.push_back(k); 
+	}
+	return pi; 
+}
+
+template <typename T>
+void KMPMatcher(const std::vector<T>& S, const std::vector<T>& P, 
+				std::vector<size_t>& ans) {
+	size_t n = S.size(), m = P.size(); 
+	std::vector<size_t> pi = ComputePrefixFunction(P); 
+	size_t q = 0; 
+	for (size_t i = 0; i < n; i++) {
+		while (q && P[q] != S[i])
+			q = pi[q]; 
+		if (P[q] == S[i])
+			q++; 
+		if (q == m) {
+			ans.push_back(i - m + 1); 
+			q = pi[q]; 
+		}
+	}
+}
+#endif
+
+#ifdef MAIN_KMPMatcher
+int main(int argc, char *argv[]) {
+	const size_t n = get_argv(argc, argv, 1, 40); 
+	const size_t m = get_argv(argc, argv, 2, 3); 
+	const size_t d = get_argv(argc, argv, 3, 2); 
+	const size_t compute = get_argv(argc, argv, 4, 1); 
+	std::vector<char> S, P; 
+	random_integers<char>(S, 'a', 'a' + d, n); 
+	random_integers<char>(P, 'a', 'a' + d, m); 
+	output_integers(S, ""); 
+	output_integers(P, ""); 
+	std::vector<size_t> ans; 
+	KMPMatcher(S, P, ans); 
+	output_integers(ans); 
+	if (compute) {
+		std::vector<size_t> ans1; 
+		NaiveStringMatcher(S, P, ans1); 
+		output_integers(ans1); 
+		std::cout << std::boolalpha << (ans == ans1) << std::endl; 
+	}
+	return 0; 
+}
+#endif
+

README.md

@@ -209,6 +209,8 @@
 | 32 | RabinKarpMatcher.cpp			| Rabin Karp Matcher					|  993 |
 | 32 | FiniteAutomatonMatcher.cpp	| Finite Automaton Matcher				|  999 |
 | 32 | FiniteAutomatonMatcher.cpp	| Compute Transition Function			| 1001 |
+| 32 | KMPMatcher.cpp				| KMP Matcher							| 1005 |
+| 32 | KMPMatcher.cpp				| Compute Prefix Function				| 1006 |
 
 # Supplementary Files
 * `utils.h`: Utils