feat: add bucket finder

QVectorSearch/mainwindow.cpp

@@ -1,6 +1,7 @@
 #include "mainwindow.h"
 #include "./ui_mainwindow.h"
 
+#include "bucket_finder.h"
 #include "finder.h"
 #include "grouped_finder.h"
 #include "linear_finder.h"
@@ -32,6 +33,7 @@ void MainWindow::setupAlgorithmSelector() {
   search_algorithms_.appendRow(new QStandardItem("Parallel search"));
   search_algorithms_.appendRow(new QStandardItem("Tree search"));
   search_algorithms_.appendRow(new QStandardItem("Grouped search"));
+  search_algorithms_.appendRow(new QStandardItem("Bucket search"));
 }
 
 void MainWindow::setupWordListSourceSelector() {
@@ -114,6 +116,9 @@ void MainWindow::createSelectedFinder() {
   case 4:
     finder_ = std::make_unique<GroupedFinder>(word_list_);
     break;
+  case 5:
+    finder_ = std::make_unique<BucketFinder>(word_list_);
+    break;
   }
 }
 

lib_vector_search/CMakeLists.txt

@@ -18,7 +18,9 @@ add_library(
   src/tree_finder.cpp
   include/tree_finder.h
   src/grouped_finder.cpp
-  include/grouped_finder.h)
+  include/grouped_finder.h
+  src/bucket_finder.cpp
+  include/bucket_finder.h)
 
 target_include_directories(vector_search PUBLIC ${PROJECT_SOURCE_DIR}/include)
 

lib_vector_search/include/bucket_finder.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include "finder.h"
+#include "word_list.h"
+
+#include <map>
+
+class Bucket {
+private:
+  std::map<const char, WordRefList> groups_;
+
+public:
+  Bucket() = default;
+
+  void insert(const WordList &word_list, size_t first_index, size_t last_index);
+
+  std::forward_list<const std::string *>
+  find_prefix(std::string_view search_term) const;
+};
+
+class BucketFinder : public Finder {
+private:
+  std::vector<Bucket> buckets_;
+
+public:
+  BucketFinder(const WordList &word_list);
+
+  std::forward_list<const std::string *>
+  find_prefix(std::string_view search_term) const override;
+};

lib_vector_search/include/word_list.h

@@ -22,6 +22,7 @@ public:
 
 class WordRefList : public std::vector<const std::string *> {
 public:
+  WordRefList() = default;
   WordRefList(const WordList &source);
 
   static void find_prefix_in_range(

lib_vector_search/src/bucket_finder.cpp

@@ -0,0 +1,84 @@
+#include "bucket_finder.h"
+
+#include <mutex>
+#include <strings.h>
+#include <thread>
+
+void Bucket::insert(const WordList &word_list, size_t first_index,
+                    size_t last_index) {
+  for (size_t index = first_index; index < last_index; ++index) {
+    const auto &current_word = word_list[index];
+    groups_[current_word.front()].push_back(&current_word);
+  }
+}
+
+std::forward_list<const std::string *>
+Bucket::find_prefix(std::string_view search_term) const {
+  const auto group = groups_.find(search_term.front());
+  if (group == groups_.cend()) {
+    return {};
+  }
+
+  std::forward_list<const std::string *> result;
+  for (const auto *word : group->second) {
+    if (word->starts_with(search_term)) {
+      result.push_front(word);
+    }
+  }
+  return result;
+}
+
+BucketFinder::BucketFinder(const WordList &word_list) {
+  if (word_list.empty()) {
+    return;
+  }
+
+  const size_t word_list_size = word_list.size();
+  const size_t bucket_count =
+      std::min<size_t>(std::thread::hardware_concurrency(), word_list_size);
+  const size_t bucket_size = word_list_size / bucket_count;
+
+  buckets_.resize(bucket_count);
+
+  std::vector<std::thread> insert_threads;
+  for (auto bucket_index = 0; bucket_index < bucket_count; ++bucket_index) {
+    const size_t first_index = bucket_index * bucket_size;
+    const size_t last_index = (bucket_index == bucket_count - 1)
+                                  ? word_list_size
+                                  : (bucket_index + 1) * bucket_size;
+
+    auto &bucket = buckets_[bucket_index];
+
+    insert_threads.emplace_back([&bucket, &word_list, first_index, last_index] {
+      bucket.insert(word_list, first_index, last_index);
+    });
+  }
+
+  for (auto &thread : insert_threads) {
+    thread.join();
+  }
+}
+
+std::forward_list<const std::string *>
+BucketFinder::find_prefix(std::string_view search_term) const {
+  std::forward_list<const std::string *> result;
+  std::mutex result_mutex;
+
+  std::vector<std::thread> search_threads;
+  for (const auto &bucket : buckets_) {
+
+    search_threads.emplace_back([&] {
+      auto thread_result = bucket.find_prefix(search_term);
+      if (!thread_result.empty()) {
+        std::lock_guard<std::mutex> result_lock(result_mutex);
+        result.merge(thread_result);
+      }
+    });
+  }
+
+  for (auto &thread : search_threads) {
+    thread.join();
+  }
+
+  return result;
+};

vector_search_cli/main.cpp

@@ -1,3 +1,4 @@
+#include "bucket_finder.h"
 #include "grouped_finder.h"
 #include "linear_finder.h"
 #include "parallel_finder.h"
@@ -54,6 +55,8 @@ int main(int argc, char *argv[]) {
 
   auto word_list = generate_word_list(5);
 
+  test_finder<BucketFinder>(word_list, "bucket finder");
+
   test_finder<LinearFinder>(word_list, "linear finder");
   test_finder<SortedLinearFinder>(word_list, "sorted linear finder");
   test_finder<ParallelFinder>(word_list, "parallel finder");