refactor: add WordRefList from WordList constructor

lib_vector_search/include/word_list.h

@@ -22,6 +22,8 @@ public:
 
 class WordRefList : public std::vector<const std::string *> {
 public:
+  WordRefList(const WordList &source);
+
   static void find_prefix_in_range(
       const WordRefList &word_list, const std::string_view &search_prefix,
       size_t start_index, size_t end_index,

lib_vector_search/src/sorted_linear_finder.cpp

@@ -1,15 +1,11 @@
 #include "sorted_linear_finder.h"
 
 #include <algorithm>
-#include <iterator>
 
 using std::forward_list, std::string, std::string_view;
 
-SortedLinearFinder::SortedLinearFinder(const WordList &word_list) {
-  std::transform(word_list.cbegin(), word_list.cend(),
-                 std::back_inserter(word_list_),
-                 [](const string &word) { return &word; });
-
+SortedLinearFinder::SortedLinearFinder(const WordList &word_list)
+    : word_list_(word_list) {
   std::sort(
       word_list_.begin(), word_list_.end(),
       [](const string *left, const string *right) { return *left < *right; });

lib_vector_search/src/word_list.cpp

@@ -77,6 +77,12 @@ void WordList::find_prefix_in_range(
   }
 };
 
+WordRefList::WordRefList(const WordList &source) {
+  for (const auto &word : source) {
+    push_back(&word);
+  }
+}
+
 void WordRefList::find_prefix_in_range(
     const WordRefList &word_list, const std::string_view &search_prefix,
     size_t start_index, size_t end_index,