feat: keep finder between searches

QVectorSearch/mainwindow.cpp

@@ -5,10 +5,11 @@
 #include "linear_finder.h"
 #include "parallel_finder.h"
 #include "timer.h"
+#include "tree_finder.h"
 #include "word_list_generator.h"
 
-#include <thread>
 #include <sstream>
+#include <thread>
 
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent), ui(new Ui::MainWindow) {
@@ -26,6 +27,7 @@ MainWindow::~MainWindow() { delete ui; }
 void MainWindow::setupAlgorithmSelector() {
   search_algorithms_.appendRow(new QStandardItem("Linear search"));
   search_algorithms_.appendRow(new QStandardItem("Parallel search"));
+  search_algorithms_.appendRow(new QStandardItem("Tree search"));
 }
 
 void MainWindow::generateWordList() {
@@ -36,13 +38,6 @@ void MainWindow::generateWordList() {
   std::stringstream status_message;
   status_message << "generated " << word_list_.size() << " words in " << timer;
   ui->mainStatusBar->showMessage(QString::fromStdString(status_message.str()));
-
-  QStringList words;
-  for (const auto &word : word_list_) {
-    words.append(QString::fromStdString(word));
-  }
-
-  result_model_.setStringList(words);
 }
 
 void MainWindow::search(const QString &search_term) {
@@ -53,32 +48,37 @@ void MainWindow::search(const QString &search_term) {
   }
 
   Timer timer;
-  const auto finder = createSelectedFinder();
-  const auto results = finder->find_prefix(search_term.toStdString());
+  const auto results = finder_->find_prefix(search_term.toStdString());
   timer.stop();
 
   std::stringstream status_message;
-  status_message << "search took " << timer << ", found " << results.size()
-                 << " results";
+  status_message << "search took " << timer << ", found "
+                 << std::distance(results.begin(), results.end()) << " results";
   ui->mainStatusBar->showMessage(QString::fromStdString(status_message.str()));
 
   showResults(results);
 }
 
-std::unique_ptr<Finder> MainWindow::createSelectedFinder() const {
+void MainWindow::createSelectedFinder() {
   auto selectedFinder = ui->searchAlgorithmSelector->currentIndex();
 
   switch (selectedFinder) {
   case 0:
   default:
-    return std::make_unique<LinearFinder>(word_list_);
+    finder_ = std::make_unique<LinearFinder>(word_list_);
+    break;
   case 1:
-    return std::make_unique<ParallelFinder>(
+    finder_ = std::make_unique<ParallelFinder>(
         word_list_, std::thread::hardware_concurrency());
+    break;
+  case 2:
+    finder_ = std::make_unique<TreeFinder>(word_list_);
+    break;
   }
 }
 
-void MainWindow::showResults(const std::vector<const std::string *> &results) {
+void MainWindow::showResults(
+    const std::forward_list<const std::string *> &results) {
   QStringList ui_results;
   for (auto word : results) {
     ui_results.append(QString::fromStdString(*word));
@@ -92,5 +92,6 @@ void MainWindow::on_searchInput_textChanged(const QString &search_term) {
 }
 
 void MainWindow::on_searchAlgorithmSelector_currentIndexChanged(int) {
+  createSelectedFinder();
   search(ui->searchInput->displayText());
 }

QVectorSearch/mainwindow.h

@@ -19,6 +19,7 @@ private:
   std::vector<std::string> word_list_;
   QStringListModel result_model_;
   QStandardItemModel search_algorithms_;
+  std::unique_ptr<Finder> finder_;
 
 public:
   MainWindow(QWidget *parent = nullptr);
@@ -28,8 +29,8 @@ private:
   void setupAlgorithmSelector();
   void generateWordList();
   void search(const QString &search_term);
-  std::unique_ptr<Finder> createSelectedFinder() const;
-  void showResults(const std::vector<const std::string *> &results);
+  void createSelectedFinder();
+  void showResults(const std::forward_list<const std::string *> &results);
 
 private slots:
   void on_searchInput_textChanged(const QString &search_term);

lib_vector_search/CMakeLists.txt

@@ -5,8 +5,18 @@ project(
   VERSION 0.1.0
   LANGUAGES CXX)
 
-add_library(vector_search STATIC src/word_list_generator.cpp src/timer.cpp
-                                 src/linear_finder.cpp src/parallel_finder.cpp)
+add_library(
+  vector_search STATIC
+  src/word_list_generator.cpp
+  include/word_list_generator.h
+  src/timer.cpp
+  include/timer.h
+  src/linear_finder.cpp
+  include/linear_finder.h
+  src/parallel_finder.cpp
+  include/parallel_finder.h
+  src/tree_finder.cpp
+  include/tree_finder.h)
 
 target_include_directories(vector_search PUBLIC ${PROJECT_SOURCE_DIR}/include)
 

lib_vector_search/include/finder.h

@@ -1,12 +1,14 @@
 #pragma once
 
+#include <forward_list>
 #include <string>
-#include <vector>
 
-using std::string, std::string_view, std::vector;
+using std::string, std::string_view, std::forward_list;
 
 class Finder {
 public:
   virtual ~Finder() = default;
-  virtual vector<const string *> find_prefix(string_view search_term) const = 0;
+
+  virtual forward_list<const string *>
+  find_prefix(string_view search_term) const = 0;
 };

lib_vector_search/include/linear_finder.h

@@ -2,11 +2,16 @@
 
 #include "finder.h"
 
+#include <vector>
+
+using std::vector;
+
 class LinearFinder : public Finder {
 private:
   const vector<string> &word_list_;
 
 public:
   LinearFinder(const vector<string> &word_list);
-  vector<const string *> find_prefix(string_view search_term) const override;
+  forward_list<const string *>
+  find_prefix(string_view search_term) const override;
 };

lib_vector_search/include/parallel_finder.h

@@ -2,12 +2,16 @@
 
 #include "finder.h"
 
+#include <vector>
+
 class ParallelFinder : public Finder {
 private:
   const size_t thread_count_;
-  const vector<string> &word_list_;
+  const std::vector<string> &word_list_;
 
 public:
-  ParallelFinder(const vector<string> &word_list, size_t thread_count);
-  vector<const string *> find_prefix(string_view search_term) const override;
+  ParallelFinder(const std::vector<string> &word_list, size_t thread_count);
+
+  std::forward_list<const std::string *>
+  find_prefix(std::string_view search_term) const override;
 };

lib_vector_search/include/tree_finder.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include "finder.h"
+
+#include <map>
+#include <vector>
+
+class SearchTreeNode {
+private:
+  std::forward_list<const std::string *> words_;
+  std::map<const char, SearchTreeNode> children_;
+
+public:
+  void insert(std::string_view partial_word, const string *original_word);
+  const SearchTreeNode *find(std::string_view search_term) const;
+
+  std::forward_list<const std::string *> words() const;
+};
+
+class SearchTree : public SearchTreeNode {
+public:
+  SearchTree(const std::vector<std::string> &word_list);
+};
+
+class TreeFinder : public Finder {
+private:
+  SearchTree search_tree_;
+
+public:
+  TreeFinder(const std::vector<string> &word_list);
+
+  virtual std::forward_list<const std::string *>
+  find_prefix(std::string_view search_term) const override;
+};

lib_vector_search/src/linear_finder.cpp

@@ -3,13 +3,13 @@
 LinearFinder::LinearFinder(const vector<string> &word_list)
     : word_list_(word_list) {}
 
-vector<const string *>
+forward_list<const string *>
 LinearFinder::find_prefix(string_view search_term) const {
-  vector<const string *> matching_words;
+  forward_list<const string *> matching_words;
 
   for (const auto &current_word : word_list_) {
     if (current_word.starts_with(search_term)) {
-      matching_words.push_back(&current_word);
+      matching_words.push_front(&current_word);
     }
   }
 

lib_vector_search/src/parallel_finder.cpp

@@ -3,15 +3,15 @@
 #include <mutex>
 #include <thread>
 
-using std::mutex, std::thread, std::lock_guard;
+using std::mutex, std::thread, std::lock_guard, std::vector, std::forward_list;
 
 ParallelFinder::ParallelFinder(const vector<string> &word_list,
                                size_t thread_count)
     : word_list_(word_list), thread_count_(thread_count) {}
 
-vector<const string *>
+forward_list<const string *>
 ParallelFinder::find_prefix(string_view search_term) const {
-  vector<const string *> result;
+  forward_list<const string *> result;
   mutex result_mutex;
 
   vector<thread> threads;
@@ -25,15 +25,19 @@ ParallelFinder::find_prefix(string_view search_term) const {
 
     threads.emplace_back(
         [](const vector<string> &word_list, const string_view &search_term,
-           vector<const string *> &result, size_t start_index, size_t end_index,
-           mutex &result_mutex) {
+           forward_list<const string *> &result, size_t start_index,
+           size_t end_index, mutex &result_mutex) {
+          forward_list<const string *> thread_results;
           for (size_t index = start_index; index < end_index; ++index) {
             const auto &current_word = word_list[index];
             if (current_word.starts_with(search_term)) {
-              const lock_guard<mutex> lock(result_mutex);
-              result.push_back(&current_word);
+              thread_results.push_front(&current_word);
             }
           }
+          if (!thread_results.empty()) {
+            const lock_guard<mutex> lock(result_mutex);
+            result.merge(thread_results);
+          }
         },
         cref(word_list_), cref(search_term), ref(result), first_word_index,
         last_word_index, ref(result_mutex));

lib_vector_search/src/tree_finder.cpp

@@ -0,0 +1,53 @@
+#include "tree_finder.h"
+
+void SearchTreeNode::insert(std::string_view partial_word,
+                            const string *original_word) {
+  if (partial_word.empty()) {
+    words_.push_front(original_word);
+  } else {
+    children_[partial_word.front()].insert(
+        std::string_view(partial_word).substr(1, partial_word.length()),
+        original_word);
+  }
+}
+
+const SearchTreeNode *SearchTreeNode::find(std::string_view search_term) const {
+  if (search_term.empty()) {
+    return this;
+  }
+
+  auto child = children_.find(search_term.front());
+  if (child != children_.cend()) {
+    return child->second.find(search_term.substr(1, search_term.length()));
+  }
+
+  return nullptr;
+}
+
+std::forward_list<const std::string *> SearchTreeNode::words() const {
+  std::forward_list<const std::string *> results(words_);
+  for (const auto &child : children_) {
+    results.merge(child.second.words());
+  }
+
+  return results;
+};
+
+SearchTree::SearchTree(const std::vector<std::string> &word_list) {
+  for (const auto &word : word_list) {
+    insert(std::string_view(word), &word);
+  }
+}
+
+TreeFinder::TreeFinder(const std::vector<string> &word_list)
+    : search_tree_(word_list) {}
+
+std::forward_list<const std::string *>
+TreeFinder::find_prefix(std::string_view search_term) const {
+  const auto *result_node = search_tree_.find(search_term);
+  if (result_node == nullptr) {
+    return {};
+  }
+
+  return result_node->words();
+}

vector_search_cli/main.cpp

@@ -1,6 +1,7 @@
 #include "linear_finder.h"
 #include "parallel_finder.h"
 #include "timer.h"
+#include "tree_finder.h"
 #include "word_list_generator.h"
 
 #include <cstdlib>
@@ -26,16 +27,15 @@ vector<string> generate_word_list() {
 void test_linear_finder(const vector<string> &word_list) {
   cout << "\nrunning linear finder" << endl;
 
-  Timer constructor_timer;
   LinearFinder linear_finder(word_list);
-  constructor_timer.stop();
 
   Timer find_timer;
   auto result = linear_finder.find_prefix("ABCD");
   find_timer.stop();
 
   cout << "linear finder took " << find_timer << endl;
-  cout << "result list is " << result.size() << " element(s) long" << endl;
+  cout << "result list is " << std::distance(result.cbegin(), result.cend())
+       << " element(s) long" << endl;
 }
 
 void test_parallel_finder(const vector<string> &word_list) {
@@ -45,16 +45,33 @@ void test_parallel_finder(const vector<string> &word_list) {
 
   cout << "using " << thread_count << " threads" << endl;
 
-  Timer constructor_timer;
   ParallelFinder parallel_finder(word_list, thread_count);
-  constructor_timer.stop();
 
   Timer find_timer;
   auto result = parallel_finder.find_prefix("ABCD");
   find_timer.stop();
 
   cout << "parallel finder took " << find_timer << endl;
-  cout << "result list is " << result.size() << " element(s) long" << endl;
+  cout << "result list is " << std::distance(result.cbegin(), result.cend())
+       << " element(s) long" << endl;
+}
+
+void test_tree_finder(const vector<string> &word_list) {
+  cout << "\nrunning tree finder" << endl;
+
+  Timer constructor_timer;
+  TreeFinder tree_finder(word_list);
+  constructor_timer.stop();
+
+  cout << "tree finder constructor took " << constructor_timer << endl;
+
+  Timer find_timer;
+  auto result = tree_finder.find_prefix("ABCD");
+  find_timer.stop();
+
+  cout << "tree finder took " << find_timer << endl;
+  cout << "result list is " << std::distance(result.cbegin(), result.cend())
+       << " element(s) long" << endl;
 }
 
 int main(int argc, char *argv[]) {
@@ -64,6 +81,7 @@ int main(int argc, char *argv[]) {
 
   test_linear_finder(word_list);
   test_parallel_finder(word_list);
+  test_tree_finder(word_list);
 
   return EXIT_SUCCESS;
 }