Repetition

alib2algo/src/string/properties/Repetition.cpp

+/*
+ * Repetition.cpp
+ *
+ *  Created on: 27.3.2020
+ *      Author: Jan Jirak
+ */
+
+#include "Repetition.h"
+#include <registration/AlgoRegistration.hpp>
+
+namespace {
+// todo Note is it necessary to register
+auto Repetition = registration::AbstractRegister < string::properties::Repetition, ext::tuple < size_t, size_t, size_t >, const string::LinearString < > & > ( string::properties::Repetition::construct );
+
+} /* namespace */

alib2algo/src/string/properties/Repetition.h

+/*
+ * Repetition.h
+ *
+ *  Created on: 27.3.2020
+ *      Author: Jan Jirak
+ */
+
+#ifndef _REPETITION_H_
+#define _REPETITION_H_
+
+#include <alib/vector>
+#include <string/LinearString.h>
+
+namespace string {
+
+namespace properties {
+
+class Repetition {
+public:
+	/**
+	 * Computes maximal repetition in a string
+	 * @param string to compute repetition for
+	 * @return Tuple of three values: repetitions first position in the string, repetitions second position in the string, length of the repetition,
+	 * in case when no repetition is present return tuple (0, 0, 0)
+	 */
+	template < class SymbolType >
+	static ext::tuple<size_t, size_t, size_t> construct(const string::LinearString < SymbolType >& string);
+};
+
+template < class SymbolType >
+ext::tuple<size_t, size_t, size_t> Repetition::construct(const string::LinearString < SymbolType >& string) {
+	const auto& x = string.getContent();
+    size_t maxlen = 0 , first = 0 , second = 0 ;
+    for ( size_t i = 0 ; i < x.size() ; ++ i ) {
+        for ( size_t j = i + 1 ; j < x.size() ; ++ j ) {
+            size_t k = 0 ;
+            while ( i + k < j && j + k < x.size() && x[i + k] == x[j + k]) ++ k ;
+            if ( k > maxlen ) {
+                maxlen = k ;
+                first = i ;
+                second = j ;
+            }
+        }
+    }
+    return ext::make_tuple(maxlen, first, second) ;
+}
+
+} /* namespace properties */
+
+} /* namespace string */
+
+#endif /* _REPETITION_H_ */