algo: covers: Update documentation, use emplace_back instead of push_back

alib2algo/src/stringology/cover/ApproximateEnhancedCoversCommon.h

@@ -13,14 +13,22 @@
 namespace stringology::cover {
+/**
+ * Auxiliary abstract class used to extract common functions used by both
+ * ApproximateEnhancedCoversComputation and
+ * RelaxedApproximateEnhancedCoversComputation.
+ */
 class ApproximateEnhancedCoversCommon {
 public:
+	/**
+	 * The purpose of this virtual destructor is to make the whole class abstract.
+	 */
 	virtual ~ApproximateEnhancedCoversCommon ( ) = 0;
 protected:
 	/**
 	 * A simple structure used to represent the element of d-subset corresponding
-	 * to a state q of a nondeterministic finite automaton.
+	 * to a state q of a nondeterministic approximate suffix automaton.
 	 */
 	struct Element {
 		unsigned depth, level;
@@ -32,12 +40,16 @@ protected:
 	 * State of the deterministic trie-like k-approximate suffix automaton.
 	 */
 	struct State {
+		 // depth is equal to the number of transitions from the starting state to
+		 // this state
 		unsigned depth = 0;
 		 // Pair of two integers - depth of the element with level 0 and length of
 		 // corresponding factor
 		ext::pair < unsigned, unsigned > lfactor;
-		ext::vector < Element >			 elements;
+
+		 // d-subset of this state
+		ext::vector < Element > elements;
 		State ( ) = default;
 		~State ( ) = default;
@@ -81,6 +93,7 @@ protected:
 	static void updateEnhCov ( const State & state, ext::set < ext::pair < unsigned, unsigned > > & enhCovers, unsigned & h ) {
 		unsigned hNext = distEnhCov ( state );
+		 // update the current set if this state covers more positions
 		if ( hNext > h ) {
 			h = hNext;
 			enhCovers.clear ( );
@@ -108,9 +121,9 @@ protected:
 		for ( size_t i = 0; i < x.getContent ( ).size ( ); ++i ) {
 			if ( symbol == x.getContent ( )[i] )
-				firstState.elements.push_back ( Element ( i + 1, 0 ) );
+				firstState.elements.emplace_back ( i + 1, 0 );
 			else if ( k > 0 )
-				firstState.elements.push_back ( Element ( i + 1, 1 ) );
+				firstState.elements.emplace_back ( i + 1, 1 );
 		}
 		return firstState;
@@ -136,10 +149,10 @@ protected:
 		for ( const auto & element : previousState.elements )
 			if ( element.depth < x.getContent ( ).size ( ) ) {
 				if ( symbol == x.getContent ( )[element.depth] ) {
-					nextState.elements.push_back ( Element ( element.depth + 1, element.level ) );
+					nextState.elements.emplace_back ( element.depth + 1, element.level );
 					nextState.lfactor = ext::pair < unsigned, unsigned > ( element.depth + 1, nextState.depth );
 				} else if ( element.level < k ) {
-					nextState.elements.push_back ( Element ( element.depth + 1, element.level + 1 ) );
+					nextState.elements.emplace_back ( element.depth + 1, element.level + 1 );
 				}
 			}