update construction of approximate matching automata

alib2algo/src/stringology/matching/HammingMatchingAutomaton.h

@@ -37,12 +37,14 @@ public:
 template < class SymbolType >
 automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int> > HammingMatchingAutomaton::construct(const string::LinearString < SymbolType > & pattern, unsigned int allowed_errors) {
-	automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int > > result( ext::make_pair(0, 0) );
+	auto initial_state = ext::make_pair(0, 0);
+
+	automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int > > result ( initial_state );
 	result.setInputAlphabet(pattern.getAlphabet());
 	// add k+1 paralel automatas (sfoeco type = exact matching) (where k is allowed_errors)
-	for (unsigned int i = 0; i<pattern.getContent().size() + 1; i++) {
-		for (unsigned int j = 0; j<allowed_errors + 1; j++) {
+	for (unsigned int j = 0; j<allowed_errors + 1; j++) {
+		for (unsigned int i = j; i<pattern.getContent().size() + 1; i++) {
 			result.addState(ext::make_pair(i, j));
 			if (i == pattern.getContent().size()) {
 				result.addFinalState(ext::make_pair(i, j));
@@ -50,15 +52,12 @@ automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int> > HammingMatc
 		}
 	}
-	for (unsigned int i = 0; i<allowed_errors + 1; i++) {
-		for (const SymbolType& symbol : pattern.getAlphabet()) {
-			auto initial_state = ext::make_pair(0, i);
-			result.addTransition(initial_state, symbol, initial_state);
-		}
+	for (const SymbolType& symbol : pattern.getAlphabet()) {
+		result.addTransition(initial_state, symbol, initial_state);
 	}
-	for (unsigned int i = 0; i<pattern.getContent().size(); i++) {
-		for (unsigned int j = 0; j < allowed_errors + 1; j++) {
+	for (unsigned int j = 0; j < allowed_errors + 1; j++) {
+		for (unsigned int i = j; i<pattern.getContent().size(); i++) {
 			auto from = ext::make_pair(i, j);
 			auto to = ext::make_pair(i+1, j);
 			result.addTransition(from, pattern.getContent()[i], to);
@@ -66,8 +65,8 @@ automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int> > HammingMatc
 	}
 	// add diagonal addTransition
-	for (unsigned int i = 0; i<pattern.getContent().size(); i++) {
-		for (unsigned int j = 0; j<allowed_errors; j++) {
+	for (unsigned int j = 0; j<allowed_errors; j++) {
+		for (unsigned int i = j; i<pattern.getContent().size(); i++) {
 			auto from = ext::make_pair(i, j);
 			auto to = ext::make_pair(i + 1, j + 1);
@@ -86,7 +85,9 @@ automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int> > HammingMatc
 template < class SymbolType >
 automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int> > HammingMatchingAutomaton::construct(const string::WildcardLinearString < SymbolType > & pattern, unsigned int allowed_errors) {
-	automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int > > result( ext::make_pair(0, 0) );
+	auto initial_state = ext::make_pair(0, 0);
+
+	automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int > > result ( initial_state );
 	result.setInputAlphabet(pattern.getAlphabet());
 	SymbolType wildcard = pattern.getWildcardSymbol();
@@ -94,8 +95,8 @@ automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int> > HammingMatc
 	alphabet_without_wildcard.erase(wildcard);
 	// add k+1 paralel automatas (sfoeco type = exact matching) (where k is allowed_errors)
-	for (unsigned int i = 0; i<pattern.getContent().size() + 1; i++) {
-		for (unsigned int j = 0; j<allowed_errors + 1; j++) {
+	for (unsigned int j = 0; j<allowed_errors + 1; j++) {
+		for (unsigned int i = j; i<pattern.getContent().size() + 1; i++) {
 			result.addState(ext::make_pair(i, j));
 			if (i == pattern.getContent().size()) {
 				result.addFinalState(ext::make_pair(i, j));
@@ -103,16 +104,12 @@ automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int> > HammingMatc
 		}
 	}
-	for (unsigned int i = 0; i<allowed_errors + 1; i++) {
-		for (const SymbolType& symbol : alphabet_without_wildcard) {
-			auto initial_state = ext::make_pair(0, i);
-
-			result.addTransition(initial_state, symbol, initial_state);
-		}
+	for (const SymbolType& symbol : alphabet_without_wildcard) {
+		result.addTransition(initial_state, symbol, initial_state);
 	}
-	for (unsigned int i = 0; i<pattern.getContent().size(); i++) {
-		for (unsigned int j = 0; j < allowed_errors + 1; j++) {
+	for (unsigned int j = 0; j < allowed_errors + 1; j++) {
+		for (unsigned int i = j; i<pattern.getContent().size(); i++) {
 			auto from = ext::make_pair(i, j);
 			auto to = ext::make_pair(i+1, j);
 			if (pattern.getContent()[i] == pattern.getWildcardSymbol()) {
@@ -126,18 +123,16 @@ automaton::NFA < SymbolType, ext::pair<unsigned int, unsigned int> > HammingMatc
 	}
 	// add diagonal addTransition
-	for (unsigned int i = 0; i<pattern.getContent().size(); i++) {
-		for (unsigned int j = 0; j<allowed_errors; j++) {
+	for (unsigned int j = 0; j<allowed_errors; j++) {
+		for (unsigned int i = j; i<pattern.getContent().size(); i++) {
 			auto from = ext::make_pair(i, j);
 			auto to = ext::make_pair(i + 1, j + 1);
-			if (pattern.getContent()[i] == wildcard) {
-				continue;
-			}
-
-			for ( const SymbolType & symbol : alphabet_without_wildcard ) {
-				if (symbol != pattern.getContent()[i]) {
-					result.addTransition(from, symbol, to);
+			if (pattern.getContent()[i] != wildcard) {
+				for ( const SymbolType & symbol : alphabet_without_wildcard ) {
+					if (symbol != pattern.getContent()[i]) {
+						result.addTransition(from, symbol, to);
+					}
 				}
 			}
 		}