use size_t in loop control variable

alib2algo/src/tree/properties/SubtreeJumpTable.h

@@ -126,7 +126,7 @@ int SubtreeJumpTable::buildDataPointersBar ( ext::vector < int > & res, const T
  */
 template < class T >
 int SubtreeJumpTable::buildDataPointersPrefixRanked ( ext::vector < int > & res, const T & subject, int begin ) {
-	for ( unsigned i = 0; i < subject.getContent ( ).size ( ); i++ )
+	for ( size_t i = 0; i < subject.getContent ( ).size ( ); i++ )
 		res.push_back ( 0 );
 	return buildDataPointersPrefixRankedInternal ( res, subject, begin );